Replace Uri.scheme == with Uri.isScheme

Use `hasScheme` in place of comparing against the empty string, and
`isScheme` to compare against all other schemes.

TEST=No behavior changes.

Change-Id: Ifc9fd13c6cf37933ebd4a754c4b500dedbcb291b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/231185
Reviewed-by: Kevin Moore <kevmoo@google.com>
Commit-Queue: Nate Bosch <nbosch@google.com>

pkg/_fe_analyzer_shared/lib/src/util/libraries_specification.dart

@@ -238,7 +238,7 @@ class LibrariesSpecification {
               _reportError(messageIncludePathIsNotAString(targetName, specUri));
             }
             Uri uri = Uri.parse(path);
-            if (uri.scheme != '' && uri.scheme != 'file') {
+            if (uri.hasScheme && !uri.isScheme('file')) {
               return _reportError(messageUnsupportedUriScheme(path, specUri));
             }
             LibrariesSpecification specification =
@@ -269,7 +269,7 @@ class LibrariesSpecification {
                 uriString, libraryName, targetName, specUri));
           }
           Uri uri = Uri.parse(uriString);
-          if (uri.scheme != '' && uri.scheme != 'file') {
+          if (uri.hasScheme && !uri.isScheme('file')) {
             return _reportError(
                 messageUnsupportedUriScheme(uriString, specUri));
           }

pkg/_fe_analyzer_shared/lib/src/util/resolve_input_uri.dart

@@ -18,7 +18,7 @@ Uri resolveInputUri(String path) {
 
 Uri parseUri(String path) {
   if (path.startsWith("file:")) {
-    if (Uri.base.scheme == "file") {
+    if (Uri.base.isScheme("file")) {
       // The Uri class doesn't handle relative file URIs correctly, the
       // following works around that issue.
       return new Uri(path: Uri.parse("x-$path").path);

pkg/_js_interop_checks/lib/js_interop_checks.dart

@@ -362,7 +362,7 @@ class JsInteropChecks extends RecursiveVisitor {
   /// or a from environment constructor.
   bool _isAllowedExternalUsage(Member member) {
     Uri uri = member.enclosingLibrary.importUri;
-    return uri.scheme == 'dart' &&
+    return uri.isScheme('dart') &&
             _pathsWithAllowedDartExternalUsage.contains(uri.path) ||
         _allowedNativeTestPatterns.any((pattern) => uri.path.contains(pattern));
   }

pkg/analysis_server/lib/src/computer/computer_hover.dart

@@ -82,7 +82,7 @@ class DartUnitHoverComputer {
           if (library != null) {
             var uri = library.source.uri;
             var analysisSession = _unit.declaredElement?.session;
-            if (uri.scheme == 'file' && analysisSession != null) {
+            if (uri.isScheme('file') && analysisSession != null) {
               // for 'file:' URIs, use the path after the project root
               var context = analysisSession.resourceProvider.pathContext;
               var projectRootDir =

pkg/analysis_server/lib/src/domains/completion/available_suggestions.dart

@@ -173,7 +173,7 @@ protocol.ElementKind protocolElementKind(DeclarationKind kind) {
 
 /// Computes the best URI to import [what] into the [unit] library.
 String? _getRelativeFileUri(DartCompletionRequest request, Uri what) {
-  if (what.scheme == 'file') {
+  if (what.isScheme('file')) {
     var pathContext = request.analysisSession.resourceProvider.pathContext;
 
     var libraryPath = request.libraryElement.source.fullName;

pkg/analysis_server/lib/src/services/correction/dart/convert_to_package_import.dart

@@ -43,14 +43,14 @@ class ConvertToPackageImport extends CorrectionProducer {
       }
 
       var importUri = uriSource.uri;
-      if (importUri.scheme != 'package') {
+      if (!importUri.isScheme('package')) {
         return;
       }
 
       // Don't offer to convert a 'package:' URI to itself.
       try {
         var uriContent = importDirective.uriContent;
-        if (uriContent == null || Uri.parse(uriContent).scheme == 'package') {
+        if (uriContent == null || Uri.parse(uriContent).isScheme('package')) {
           return;
         }
       } on FormatException {

pkg/analysis_server/lib/src/services/correction/dart/convert_to_relative_import.dart

@@ -45,7 +45,7 @@ class ConvertToRelativeImport extends CorrectionProducer {
 
     // Ignore if the uri is not a package: uri.
     var sourceUri = resolvedResult.uri;
-    if (sourceUri.scheme != 'package') {
+    if (!sourceUri.isScheme('package')) {
       return;
     }
 
@@ -61,7 +61,7 @@ class ConvertToRelativeImport extends CorrectionProducer {
     }
 
     // Ignore if import uri is not a package: uri.
-    if (importUri.scheme != 'package') {
+    if (!importUri.isScheme('package')) {
       return;
     }
 

pkg/analysis_server/lib/src/services/correction/util.dart

@@ -322,7 +322,7 @@ Map<String, Element> getImportNamespace(ImportElement imp) {
 /// Computes the best URI to import [what] into [from].
 String getLibrarySourceUri(
     path.Context pathContext, LibraryElement from, Uri what) {
-  if (what.scheme == 'file') {
+  if (what.isScheme('file')) {
     var fromFolder = pathContext.dirname(from.source.fullName);
     var relativeFile = pathContext.relative(what.path, from: fromFolder);
     return pathContext.split(relativeFile).join('/');

pkg/analyzer/lib/src/file_system/file_system.dart

@@ -37,5 +37,5 @@ class ResourceUriResolver extends UriResolver {
   Uri restoreAbsolute(Source source) => pathToUri(source.fullName);
 
   /// Return `true` if the given [uri] is a `file` URI.
-  static bool isFileUri(Uri uri) => uri.scheme == FILE_SCHEME;
+  static bool isFileUri(Uri uri) => uri.isScheme(FILE_SCHEME);
 }

pkg/analyzer/lib/src/generated/source.dart

@@ -31,7 +31,7 @@ abstract class BasicSource extends Source {
 
   @Deprecated('Use uri.isScheme("dart") instead')
   @override
-  bool get isInSystemLibrary => uri.scheme == 'dart';
+  bool get isInSystemLibrary => uri.isScheme('dart');
 
   @override
   String get shortName => pathos.basename(fullName);

pkg/analyzer/lib/src/source/package_map_resolver.dart

@@ -79,6 +79,6 @@ class PackageMapUriResolver extends UriResolver {
 
   /// Returns `true` if [uri] is a `package` URI.
   static bool isPackageUri(Uri uri) {
-    return uri.scheme == PACKAGE_SCHEME;
+    return uri.isScheme(PACKAGE_SCHEME);
   }
 }

pkg/analyzer/lib/src/source/source_resource.dart

@@ -80,7 +80,7 @@ class FileSource extends Source {
 
   @Deprecated('Use uri.isScheme("dart") instead')
   @override
-  bool get isInSystemLibrary => uri.scheme == DartUriResolver.DART_SCHEME;
+  bool get isInSystemLibrary => uri.isScheme(DartUriResolver.DART_SCHEME);
 
   @Deprecated('Not used anymore')
   @override

pkg/analyzer/lib/src/workspace/bazel.dart

@@ -83,7 +83,7 @@ class BazelPackageUriResolver extends UriResolver {
   }
 
   Source? _resolveAbsolute(Uri uri) {
-    if (uri.scheme == 'file') {
+    if (uri.isScheme('file')) {
       var path = fileUriToNormalizedPath(_context, uri);
       var pathRelativeToRoot = _workspace._relativeToRoot(path);
       if (pathRelativeToRoot == null) return null;
@@ -91,7 +91,7 @@ class BazelPackageUriResolver extends UriResolver {
       var file = _workspace.findFile(fullFilePath);
       return file?.createSource(uri);
     }
-    if (uri.scheme != 'package') {
+    if (!uri.isScheme('package')) {
       return null;
     }
     String uriPath = Uri.decodeComponent(uri.path);

pkg/analyzer/lib/src/workspace/package_build.dart

@@ -73,7 +73,7 @@ class PackageBuildPackageUriResolver extends UriResolver {
 
   @override
   Source? resolveAbsolute(Uri uri) {
-    if (uri.scheme != 'package') {
+    if (!uri.isScheme('package')) {
       return null;
     }
 

pkg/analyzer/lib/src/workspace/workspace.dart

@@ -82,7 +82,7 @@ abstract class WorkspacePackage {
   /// example, the case of a [InSummarySource]). In this case, use
   /// [workspace]'s package URI resolver to fetch the file path.
   String? filePathFromSource(Source source) {
-    if (source.uri.scheme == 'package') {
+    if (source.uri.isScheme('package')) {
       return workspace.packageUriResolver.resolveAbsolute(source.uri)?.fullName;
     } else {
       return source.fullName;

pkg/analyzer/test/generated/test_support.dart

@@ -530,9 +530,9 @@ class TestSourceWithUri extends TestSource {
   @Deprecated('Use Source.uri instead')
   @override
   UriKind get uriKind {
-    if (uri.scheme == 'dart') {
+    if (uri.isScheme('dart')) {
       return UriKind.DART_URI;
-    } else if (uri.scheme == 'package') {
+    } else if (uri.isScheme('package')) {
       return UriKind.PACKAGE_URI;
     }
     return UriKind.FILE_URI;

pkg/analyzer/test/src/dart/analysis/file_state_test.dart

@@ -783,7 +783,7 @@ part of 'a.dart';
       if (file is LibraryCycle) {
         return !file.libraries.any((file) => file.uri.isScheme('dart'));
       } else if (file is FileState) {
-        return file.uri.scheme != 'dart';
+        return !file.uri.isScheme('dart');
       } else if (file == null) {
         return true;
       } else {

pkg/analyzer_cli/lib/src/analyzer_impl.dart

@@ -127,7 +127,7 @@ class AnalyzerImpl {
     files.clear();
     errorsResults.clear();
     var libraryUri = libraryFile.uri;
-    if (libraryUri.scheme == 'package' && libraryUri.pathSegments.isNotEmpty) {
+    if (libraryUri.isScheme('package') && libraryUri.pathSegments.isNotEmpty) {
       _selfPackageName = libraryUri.pathSegments[0];
     }
   }
@@ -177,7 +177,7 @@ class AnalyzerImpl {
 
   /// Determine whether the given URI refers to a package being analyzed.
   bool _isAnalyzedPackage(Uri uri) {
-    if (uri.scheme != 'package' || uri.pathSegments.isEmpty) {
+    if (!uri.isScheme('package') || uri.pathSegments.isEmpty) {
       return false;
     }
     var packageName = uri.pathSegments.first;

pkg/build_integration/lib/file_system/multi_root.dart

@@ -52,7 +52,7 @@ class MultiRootFileSystemEntity implements FileSystemEntity {
       _delegate ??= await _resolveEntity();
 
   Future<FileSystemEntity> _resolveEntity() async {
-    if (uri.scheme == multiRootFileSystem.markerScheme) {
+    if (uri.isScheme(multiRootFileSystem.markerScheme)) {
       if (!uri.isAbsolute) {
         throw new FileSystemException(
             uri, "This MultiRootFileSystem only handles absolutes URIs: $uri");

pkg/build_integration/lib/file_system/single_root.dart

@@ -33,7 +33,7 @@ class SingleRootFileSystem implements FileSystem {
 
   @override
   FileSystemEntity entityForUri(Uri uri) {
-    if (uri.scheme != markerScheme) {
+    if (!uri.isScheme(markerScheme)) {
       throw new FileSystemException(
           uri,
           "This SingleRootFileSystem only handles URIs with the '$markerScheme'"

pkg/compiler/lib/src/compiler.dart

@@ -726,7 +726,7 @@ abstract class Compiler {
   Uri getCanonicalUri(Entity element) {
     Uri libraryUri = _uriFromElement(element);
     if (libraryUri == null) return null;
-    if (libraryUri.scheme == 'package') {
+    if (libraryUri.isScheme('package')) {
       int slashPos = libraryUri.path.indexOf('/');
       if (slashPos != -1) {
         String packageName = libraryUri.path.substring(0, slashPos);

pkg/compiler/lib/src/dart2js.dart

@@ -1102,7 +1102,7 @@ class AbortLeg {
 
 void writeString(Uri uri, String text) {
   if (!enableWriteString) return;
-  if (uri.scheme != 'file') {
+  if (!uri.isScheme('file')) {
     fail('Unhandled scheme ${uri.scheme}.');
   }
   var file = (File(uri.toFilePath())..createSync(recursive: true))

pkg/compiler/lib/src/diagnostics/code_location.dart

@@ -18,7 +18,7 @@ abstract class CodeLocation {
   String relativize(Uri baseUri);
 
   factory CodeLocation(Uri uri) {
-    if (uri.scheme == 'package') {
+    if (uri.isScheme('package')) {
       int slashPos = uri.path.indexOf('/');
       if (slashPos != -1) {
         String packageName = uri.path.substring(0, slashPos);
@@ -42,7 +42,7 @@ class SchemeLocation implements CodeLocation {
 
   @override
   bool inSameLocation(Uri uri) {
-    return this.uri.scheme == uri.scheme;
+    return this.uri.isScheme(uri.scheme);
   }
 
   @override
@@ -62,7 +62,7 @@ class PackageLocation implements CodeLocation {
 
   @override
   bool inSameLocation(Uri uri) {
-    return uri.scheme == 'package' && uri.path.startsWith('$packageName/');
+    return uri.isScheme('package') && uri.path.startsWith('$packageName/');
   }
 
   @override

pkg/compiler/lib/src/elements/entity_utils.dart

@@ -19,17 +19,17 @@ int compareLibrariesUris(Uri a, Uri b) {
   }
 
   // Order: platform < package < other.
-  if (a.scheme == 'dart') {
+  if (a.isScheme('dart')) {
-    if (b.scheme == 'dart') return byCanonicalUriPath();
+    if (b.isScheme('dart')) return byCanonicalUriPath();
     return -1;
   }
-  if (b.scheme == 'dart') return 1;
+  if (b.isScheme('dart')) return 1;
 
-  if (a.scheme == 'package') {
+  if (a.isScheme('package')) {
-    if (b.scheme == 'package') return byCanonicalUriPath();
+    if (b.isScheme('package')) return byCanonicalUriPath();
     return -1;
   }
-  if (b.scheme == 'package') return 1;
+  if (b.isScheme('package')) return 1;
 
   return _compareCanonicalUri(a, b);
 }

pkg/compiler/lib/src/ir/util.dart

@@ -251,7 +251,7 @@ bool containsFreeVariables(ir.DartType type) =>
 
 /// Returns true if [importUri] corresponds to dart:html and related libraries.
 bool _isWebLibrary(Uri importUri) =>
-    importUri.scheme == 'dart' &&
+    importUri.isScheme('dart') &&
         (importUri.path == 'html' ||
             importUri.path == 'svg' ||
             importUri.path == 'indexed_db' ||

pkg/compiler/lib/src/js_backend/annotations.dart

@@ -156,7 +156,7 @@ EnumSet<PragmaAnnotation> processMemberAnnotations(
 
   Uri uri = member.enclosingLibrary.importUri;
   bool platformAnnotationsAllowed =
-      options.testMode || uri.scheme == 'dart' || maybeEnableNative(uri);
+      options.testMode || uri.isScheme('dart') || maybeEnableNative(uri);
 
   for (PragmaAnnotationData data in pragmaAnnotationData) {
     String name = data.name;

pkg/compiler/lib/src/js_backend/backend_usage.dart

@@ -158,7 +158,7 @@ class BackendUsageBuilderImpl implements BackendUsageBuilder {
   bool _isValidBackendUse(Entity element, LibraryEntity library) {
     if (_isValidEntity(element)) return true;
     SourceSpan span = _frontendStrategy.spanFromSpannable(element, element);
-    if (library.canonicalUri.scheme == 'dart' &&
+    if (library.canonicalUri.isScheme('dart') &&
         span.uri.path.contains('_internal/js_runtime/lib/')) {
       // TODO(johnniwinther): We should be more precise about these.
       return true;

pkg/compiler/lib/src/kernel/dart2js_target.dart

@@ -55,7 +55,7 @@ bool allowedNativeTest(Uri uri) {
 
 bool maybeEnableNative(Uri uri) {
   bool allowedDartLibrary() {
-    if (uri.scheme != 'dart') return false;
+    if (!uri.isScheme('dart')) return false;
     return _allowedDartSchemePaths.contains(uri.path);
   }
 
@@ -118,7 +118,7 @@ class Dart2jsTarget extends Target {
   bool allowPlatformPrivateLibraryAccess(Uri importer, Uri imported) =>
       super.allowPlatformPrivateLibraryAccess(importer, imported) ||
       maybeEnableNative(importer) ||
-      (importer.scheme == 'package' &&
+      (importer.isScheme('package') &&
           importer.path.startsWith('dart2js_runtime_metrics/'));
 
   @override

pkg/compiler/lib/src/kernel/front_end_adapter.dart

@@ -23,7 +23,7 @@ class CompilerFileSystem implements fe.FileSystem {
 
   @override
   fe.FileSystemEntity entityForUri(Uri uri) {
-    if (uri.scheme == 'data') {
+    if (uri.isScheme('data')) {
       return fe.DataFileSystemEntity(Uri.base.resolveUri(uri));
     } else {
       return _CompilerFileSystemEntity(uri, this);

pkg/compiler/lib/src/kernel/loader.dart

@@ -269,7 +269,7 @@ class KernelLoaderTask extends CompilerTask {
 
       // Libraries dependencies do not show implicit imports to `dart:core`.
       var dartCore = component.libraries.firstWhere((lib) {
-        return lib.importUri.scheme == 'dart' && lib.importUri.path == 'core';
+        return lib.importUri.isScheme('dart') && lib.importUri.path == 'core';
       });
       search(dartCore);
 

pkg/compiler/lib/src/options.dart

@@ -826,7 +826,7 @@ class CompilerOptions implements DiagnosticOptions {
       return true;
     }
     if (shownPackageWarnings != null) {
-      return uri.scheme == 'package' &&
+      return uri.isScheme('package') &&
           shownPackageWarnings!.contains(uri.pathSegments.first);
     }
     return false;

pkg/compiler/lib/src/source_file_provider.dart

@@ -40,9 +40,9 @@ abstract class SourceFileProvider implements CompilerInput {
     }
     if (input != null) return Future.value(input);
 
-    if (resourceUri.scheme == 'file') {
+    if (resourceUri.isScheme('file')) {
       return _readFromFile(resourceUri, inputKind);
-    } else if (resourceUri.scheme == 'http' || resourceUri.scheme == 'https') {
+    } else if (resourceUri.isScheme('http') || resourceUri.isScheme('https')) {
       return _readFromHttp(resourceUri, inputKind);
     } else {
       throw ArgumentError("Unknown scheme in uri '$resourceUri'");
@@ -50,7 +50,7 @@ abstract class SourceFileProvider implements CompilerInput {
   }
 
   api.Input _readFromFileSync(Uri resourceUri, api.InputKind inputKind) {
-    assert(resourceUri.scheme == 'file');
+    assert(resourceUri.isScheme('file'));
     List<int> source;
     try {
       source = readAll(resourceUri.toFilePath(),
@@ -99,7 +99,7 @@ abstract class SourceFileProvider implements CompilerInput {
 
   Future<api.Input<List<int>>> _readFromHttp(
       Uri resourceUri, api.InputKind inputKind) {
-    assert(resourceUri.scheme == 'http');
+    assert(resourceUri.isScheme('http'));
     HttpClient client = HttpClient();
     return client
         .getUrl(resourceUri)
@@ -279,7 +279,7 @@ class FormattingDiagnosticHandler implements CompilerDiagnostics {
       api.Input file = provider.getUtf8SourceFile(uri);
       if (file == null &&
           autoReadFileUri &&
-          (uri.scheme == 'file' || !uri.isAbsolute) &&
+          (uri.isScheme('file') || !uri.isAbsolute) &&
           uri.path.endsWith('.dart')) {
         if (!uri.isAbsolute) {
           uri = provider.cwd.resolveUri(uri);
@@ -379,7 +379,7 @@ class RandomAccessFileOutputProvider implements CompilerOutput {
     Uri uri = createUri(name, extension, type);
     bool isPrimaryOutput = uri == out;
 
-    if (uri.scheme != 'file') {
+    if (!uri.isScheme('file')) {
       onFailure('Unhandled scheme ${uri.scheme} in $uri.');
     }
 
@@ -428,7 +428,7 @@ class RandomAccessFileOutputProvider implements CompilerOutput {
 
     allOutputFiles.add(fe.relativizeUri(Uri.base, uri, Platform.isWindows));
 
-    if (uri.scheme != 'file') {
+    if (!uri.isScheme('file')) {
       onFailure('Unhandled scheme ${uri.scheme} in $uri.');
     }
 
@@ -608,7 +608,7 @@ class MultiRootInputProvider extends SourceFileProvider {
   Future<api.Input<List<int>>> readFromUri(Uri uri,
       {InputKind inputKind = InputKind.UTF8}) async {
     var resolvedUri = uri;
-    if (resolvedUri.scheme == markerScheme) {
+    if (resolvedUri.isScheme(markerScheme)) {
       var path = resolvedUri.path;
       if (path.startsWith('/')) path = path.substring(1);
       for (var dir in roots) {
@@ -634,7 +634,7 @@ class MultiRootInputProvider extends SourceFileProvider {
 
   @override
   api.Input autoReadFromFile(Uri resourceUri) {
-    if (resourceUri.scheme == markerScheme) {
+    if (resourceUri.isScheme(markerScheme)) {
       var path = resourceUri.path;
       for (var dir in roots) {
         var file = dir.resolve(path);

pkg/compiler/test/analyses/analysis_helper.dart

@@ -40,7 +40,7 @@ main(List<String> args) {
   Uri packageConfig = getPackages(argResults);
   List<String> options = getOptions(argResults);
   run(entryPoint, null,
-      analyzedUrisFilter: (Uri uri) => uri.scheme != 'dart',
+      analyzedUrisFilter: (Uri uri) => !uri.isScheme('dart'),
       librariesSpecificationUri: librariesSpecificationUri,
       packageConfig: packageConfig,
       options: options);
@@ -362,7 +362,7 @@ class DynamicVisitor extends StaticTypeVisitorBase {
   String reportAssertionFailure(ir.Node node, String message) {
     SourceSpan span = computeSourceSpanFromTreeNode(node);
     Uri uri = span.uri;
-    if (uri.scheme == 'org-dartlang-sdk') {
+    if (uri.isScheme('org-dartlang-sdk')) {
       span = new SourceSpan(
           Uri.base.resolve(uri.path.substring(1)), span.begin, span.end);
     }
@@ -378,7 +378,7 @@ class DynamicVisitor extends StaticTypeVisitorBase {
     String uriString = relativizeUri(Uri.base, uri, Platform.isWindows);
     Map<String, List<DiagnosticMessage>> actualMap = _actualMessages
         .putIfAbsent(uriString, () => <String, List<DiagnosticMessage>>{});
-    if (uri.scheme == 'org-dartlang-sdk') {
+    if (uri.isScheme('org-dartlang-sdk')) {
       span = new SourceSpan(
           Uri.base.resolve(uri.path.substring(1)), span.begin, span.end);
     }

pkg/compiler/test/analyses/api_dynamic_test.dart

@@ -14,7 +14,7 @@ main(List<String> args) {
   asyncTest(() async {
     await run(
         Uri.parse('memory:main.dart'), 'pkg/compiler/test/analyses/$goldenFile',
-        analyzedUrisFilter: (Uri uri) => uri.scheme == 'dart',
+        analyzedUrisFilter: (Uri uri) => uri.isScheme('dart'),
         memorySourceFiles: {'main.dart': 'main() {}'},
         verbose: args.contains('-v'),
         generate: args.contains('-g'));

pkg/compiler/test/end_to_end/modular_loader_test.dart

@@ -109,7 +109,7 @@ class TestFileSystem implements FileSystem {
 
   @override
   FileSystemEntity entityForUri(Uri uri) {
-    if (uri.scheme == 'file') return physical.entityForUri(uri);
+    if (uri.isScheme('file')) return physical.entityForUri(uri);
     return memory.entityForUri(uri);
   }
 }

pkg/compiler/test/equivalence/id_equivalence_helper.dart

@@ -248,8 +248,8 @@ Future<CompiledData<T>> computeData<T>(String name, Uri entryPoint,
 
   bool excludeLibrary(LibraryEntity library) {
     return forUserLibrariesOnly &&
-        (library.canonicalUri.scheme == 'dart' ||
+        (library.canonicalUri.isScheme('dart') ||
-            library.canonicalUri.scheme == 'package');
+            library.canonicalUri.isScheme('package'));
   }
 
   ir.Library getIrLibrary(LibraryEntity library) {

pkg/compiler/test/equivalence/show_helper.dart

@@ -65,7 +65,7 @@ show<T>(ArgResults argResults, DataComputer<T> dataComputer,
     SourceFileProvider provider = data.compiler.provider;
     for (Uri uri in data.actualMaps.keys) {
       Uri fileUri = uri;
-      if (fileUri.scheme == 'org-dartlang-sdk') {
+      if (fileUri.isScheme('org-dartlang-sdk')) {
         fileUri = Uri.base.resolve(fileUri.path.substring(1));
       }
       if (show != null && !show.any((f) => '$fileUri'.endsWith(f))) {

pkg/compiler/test/helpers/element_lookup.dart

@@ -21,8 +21,8 @@ ClassEntity findClass(JClosedWorld closedWorld, String name) {
       closedWorld.commonElements.jsHelperLibrary, name);
   if (cls == null) {
     for (LibraryEntity library in elementEnvironment.libraries) {
-      if (library.canonicalUri.scheme != 'dart' &&
+      if (!library.canonicalUri.isScheme('dart') &&
-          library.canonicalUri.scheme != 'package') {
+          !library.canonicalUri.isScheme('package')) {
         cls = elementEnvironment.lookupClass(library, name);
         if (cls != null) {
           break;
@@ -70,8 +70,8 @@ MemberEntity findMember(JClosedWorld closedWorld, String name) {
       setter: isSetter);
   if (member == null) {
     for (LibraryEntity library in elementEnvironment.libraries) {
-      if (library.canonicalUri.scheme != 'dart' &&
+      if (!library.canonicalUri.isScheme('dart') &&
-          library.canonicalUri.scheme != 'package') {
+          !library.canonicalUri.isScheme('package')) {
         member = elementEnvironment.lookupLibraryMember(library, name,
             setter: isSetter);
         if (member != null) {

pkg/compiler/test/helpers/memory_source_file_helper.dart

@@ -31,7 +31,7 @@ class MemorySourceFileProvider extends SourceFileProvider {
   @override
   Future<Input<List<int>>> readBytesFromUri(
       Uri resourceUri, InputKind inputKind) {
-    if (resourceUri.scheme != 'memory') {
+    if (!resourceUri.isScheme('memory')) {
       return super.readBytesFromUri(resourceUri, inputKind);
     }
     // TODO(johnniwinther): We should use inputs already in the cache. Some

pkg/compiler/test/model/cfe_annotations_test.dart

@@ -351,7 +351,7 @@ main(List<String> args) {
         }
 
         for (ir.Library library in component.libraries) {
-          if (library.importUri.scheme == 'memory') {
+          if (library.importUri.isScheme('memory')) {
             String libraryId = library.importUri.path;
             LibraryEntity libraryEntity = elementMap.getLibrary(library);
 

pkg/compiler/test/model/receiver_type_test.dart

@@ -52,7 +52,7 @@ Future runTest() async {
   Selector callSelector = new Selector.callClosure(0);
   closedWorld.classHierarchy.forEachStrictSubclassOf(
       closedWorld.commonElements.objectClass, (ClassEntity cls) {
-    if (cls.library.canonicalUri.scheme != 'memory')
+    if (!cls.library.canonicalUri.isScheme('memory'))
       return IterationStep.CONTINUE;
 
     TypeMask mask = new TypeMask.nonNullSubclass(cls, closedWorld);

pkg/compiler/test/sourcemaps/tools/source_mapping_tester.dart

@@ -157,7 +157,7 @@ Future<TestResult> runTests(
       .process(['--csp', Flags.disableInlining, ...options], verbose: verbose);
   TestResult result = new TestResult(config, filename, processor);
   for (SourceMapInfo info in sourceMaps.elementSourceMapInfos.values) {
-    if (info.element.library.canonicalUri.scheme == 'dart') continue;
+    if (info.element.library.canonicalUri.isScheme('dart')) continue;
     result.userInfoList.add(info);
     Iterable<CodePoint> missingCodePoints =
         info.codePoints.where((c) => c.isMissing);

pkg/compiler/tool/modular_test_suite_helper.dart

@@ -638,7 +638,7 @@ Future<void> resolveScripts(Options options) async {
       String sourceUriOrPath, String relativeSnapshotPath) async {
     Uri sourceUri = sdkRoot.resolve(sourceUriOrPath);
     String result =
-        sourceUri.scheme == 'file' ? sourceUri.toFilePath() : sourceUriOrPath;
+        sourceUri.isScheme('file') ? sourceUri.toFilePath() : sourceUriOrPath;
     if (_options.useSdk) {
       String snapshot = Uri.file(Platform.resolvedExecutable)
           .resolve(relativeSnapshotPath)

pkg/dart2js_info/bin/src/deferred_library_layout.dart

@@ -64,7 +64,7 @@ _showLayout(String file) async {
     print('  contains:');
     map.forEach((lib, elements) {
       var uri = lib.uri;
-      var shortUri = (uri.scheme == 'file' && uri.path.startsWith(dir))
+      var shortUri = (uri.isScheme('file') && uri.path.startsWith(dir))
           ? uri.path.substring(dir.length + 1)
           : '$uri';
 

pkg/dart2js_info/lib/deferred_library_check.dart

@@ -133,7 +133,7 @@ LibraryInfo _getLibraryOf(Info info) {
   return current;
 }
 
-bool _isPackageUri(Uri uri) => uri.scheme == 'package';
+bool _isPackageUri(Uri uri) => uri.isScheme('package');
 
 String _getPackageName(Uri uri) {
   assert(_isPackageUri(uri));

pkg/dart2js_info/lib/src/util.dart

@@ -116,7 +116,7 @@ String packageName(Info info) {
     info = info.parent;
   }
   if (info is LibraryInfo) {
-    if (info.uri.scheme == 'package') {
+    if (info.uri.isScheme('package')) {
       return '${info.uri}'.split('/').first;
     }
   }

pkg/dart2js_tools/lib/deobfuscate_stack_trace.dart

@@ -31,7 +31,7 @@ String deobfuscateStackTrace(String obfuscatedTrace) {
   var provider = CachingFileProvider();
   StackDeobfuscationResult result = deobfuscateStack(obfuscatedTrace, provider);
   Frame firstFrame = result.original.frames.first;
-  String translatedError = (firstFrame.uri.scheme == 'error'
+  String translatedError = (firstFrame.uri.isScheme('error')
           ? null
           : translate(error, provider.mappingFor(firstFrame.uri))) ??
       '<no error message found>';

pkg/dart2js_tools/lib/src/util.dart

@@ -34,7 +34,7 @@ class CachingFileProvider implements FileProvider {
 /// deobfuscation locally for debugging purposes.
 class DownloadedFileProvider extends CachingFileProvider {
   _localize(uri) {
-    if (uri.scheme == 'http' || uri.scheme == 'https') {
+    if (uri.isScheme('http') || uri.isScheme('https')) {
       String filename = uri.path.substring(uri.path.lastIndexOf('/') + 1);
       return Uri.base.resolve(filename);
     }

pkg/dds/lib/dds.dart

@@ -46,13 +46,13 @@ abstract class DartDevelopmentService {
     DevToolsConfiguration? devToolsConfiguration,
     bool logRequests = false,
   }) async {
-    if (remoteVmServiceUri.scheme != 'http') {
+    if (!remoteVmServiceUri.isScheme('http')) {
       throw ArgumentError(
         'remoteVmServiceUri must have an HTTP scheme. Actual: ${remoteVmServiceUri.scheme}',
       );
     }
     if (serviceUri != null) {
-      if (serviceUri.scheme != 'http') {
+      if (!serviceUri.isScheme('http')) {
         throw ArgumentError(
           'serviceUri must have an HTTP scheme. Actual: ${serviceUri.scheme}',
         );

pkg/dev_compiler/lib/src/compiler/module_builder.dart

@@ -460,11 +460,11 @@ class AmdModuleBuilder extends _ModuleBuilder {
 }
 
 bool isSdkInternalRuntimeUri(Uri importUri) {
-  return importUri.scheme == 'dart' && importUri.path == '_runtime';
+  return importUri.isScheme('dart') && importUri.path == '_runtime';
 }
 
 String libraryUriToJsIdentifier(Uri importUri) {
-  if (importUri.scheme == 'dart') {
+  if (importUri.isScheme('dart')) {
     return isSdkInternalRuntimeUri(importUri) ? 'dart' : importUri.path;
   }
   return pathToJSIdentifier(p.withoutExtension(importUri.pathSegments.last));

pkg/dev_compiler/lib/src/compiler/shared_command.dart

@@ -347,7 +347,7 @@ Uri sourcePathToUri(String source, {bool windows}) {
 
 Uri sourcePathToRelativeUri(String source, {bool windows}) {
   var uri = sourcePathToUri(source, windows: windows);
-  if (uri.scheme == 'file') {
+  if (uri.isScheme('file')) {
     var uriPath = uri.path;
     var root = Uri.base.path;
     if (uriPath.startsWith(root)) {
@@ -400,7 +400,7 @@ Map placeSourceMap(Map sourceMap, String sourceMapPath, String multiRootScheme,
       return sourcePath;
     }
 
-    if (uri.scheme == 'http') return sourcePath;
+    if (uri.isScheme('http')) return sourcePath;
 
     // Convert to a local file path if it's not.
     sourcePath = sourcePathToUri(p.absolute(p.fromUri(uri))).path;

pkg/dev_compiler/lib/src/kernel/asset_file_system.dart

@@ -32,7 +32,7 @@ class AssetFileSystem implements FileSystem {
 
   @override
   FileSystemEntity entityForUri(Uri uri) {
-    if (uri.scheme == 'file') {
+    if (uri.isScheme('file')) {
       return original.entityForUri(uri);
     }
 

pkg/dev_compiler/lib/src/kernel/command.dart

@@ -177,7 +177,7 @@ Future<CompilerResult> _compile(List<String> args,
       options.multiRootScheme, multiRootPaths, fe.StandardFileSystem.instance);
 
   Uri toCustomUri(Uri uri) {
-    if (uri.scheme == '') {
+    if (!uri.hasScheme) {
       return Uri(scheme: options.multiRootScheme, path: '/' + uri.path);
     }
     return uri;
@@ -486,7 +486,7 @@ Future<CompilerResult> _compile(List<String> args,
       compilerState.incrementalCompiler.updateNeededDillLibrariesWithHierarchy(
           neededDillLibraries, result.classHierarchy);
       for (var lib in neededDillLibraries) {
-        if (lib.importUri.scheme == 'dart') continue;
+        if (lib.importUri.isScheme('dart')) continue;
         var uri = compilerState.libraryToInputDill[lib.importUri];
         if (uri == null) {
           throw StateError('Library ${lib.importUri} was recorded as used, '
@@ -552,7 +552,7 @@ Future<CompilerResult> compileSdkFromDill(List<String> args) async {
   var component = loadComponentFromBinary(inputs.single);
   var invalidLibraries = <Uri>[];
   for (var library in component.libraries) {
-    if (library.importUri.scheme != 'dart') {
+    if (!library.importUri.isScheme('dart')) {
       invalidLibraries.add(library.importUri);
     }
   }

pkg/dev_compiler/lib/src/kernel/compiler.dart

@@ -496,10 +496,10 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
   @override
   String jsLibraryAlias(Library library) {
     var uri = library.importUri.normalizePath();
-    if (uri.scheme == 'dart') return null;
+    if (uri.isScheme('dart')) return null;
 
     Iterable<String> segments;
-    if (uri.scheme == 'package') {
+    if (uri.isScheme('package')) {
       // Strip the package name.
       segments = uri.pathSegments.skip(1);
     } else {
@@ -521,7 +521,7 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
   /// True when [library] is the sdk internal library 'dart:_internal'.
   bool _isDartInternal(Library library) {
     var importUri = library.importUri;
-    return importUri.scheme == 'dart' && importUri.path == '_internal';
+    return importUri.isScheme('dart') && importUri.path == '_internal';
   }
 
   @override
@@ -531,7 +531,7 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
 
   @override
   String libraryToModule(Library library) {
-    if (library.importUri.scheme == 'dart') {
+    if (library.importUri.isScheme('dart')) {
       // TODO(jmesserly): we need to split out HTML.
       return js_ast.dartSdkModule;
     }
@@ -1940,7 +1940,7 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
 
   bool _isForwardingStub(Procedure member) {
     if (member.isForwardingStub || member.isForwardingSemiStub) {
-      if (_currentLibrary.importUri.scheme != 'dart') return true;
+      if (!_currentLibrary.importUri.isScheme('dart')) return true;
       // TODO(jmesserly): external methods in the SDK seem to get incorrectly
       // tagged as forwarding stubs even if they are patched. Perhaps there is
       // an ordering issue in CFE. So for now we pattern match to see if it
@@ -2254,7 +2254,7 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
         _hierarchy.getClassAsInstanceOf(c.superclass, _coreTypes.iterableClass);
     if (parentIterable != null) return null;
 
-    if (c.enclosingLibrary.importUri.scheme == 'dart' &&
+    if (c.enclosingLibrary.importUri.isScheme('dart') &&
         c.procedures.any((m) => _jsExportName(m) == 'Symbol.iterator')) {
       return null;
     }
@@ -2764,7 +2764,7 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
     var fn = _emitFunction(p.function, p.name.text)
       ..sourceInformation = _nodeEnd(p.fileEndOffset);
 
-    if (_currentLibrary.importUri.scheme == 'dart' &&
+    if (_currentLibrary.importUri.isScheme('dart') &&
         _isInlineJSFunction(p.function.body)) {
       fn = js_ast.simplifyPassThroughArrowFunCallBody(fn);
     }
@@ -3737,7 +3737,7 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
 
   bool _reifyGenericFunction(Member m) =>
       m == null ||
-      m.enclosingLibrary.importUri.scheme != 'dart' ||
+      !m.enclosingLibrary.importUri.isScheme('dart') ||
       !m.annotations
           .any((a) => isBuiltinAnnotation(a, '_js_helper', 'NoReifyGeneric'));
 
@@ -5692,7 +5692,7 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
 
   bool _isWebLibrary(Uri importUri) =>
       importUri != null &&
-      importUri.scheme == 'dart' &&
+      importUri.isScheme('dart') &&
       (importUri.path == 'html' ||
           importUri.path == 'svg' ||
           importUri.path == 'indexed_db' ||
@@ -5792,7 +5792,7 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
 
     if (args.positional.isEmpty &&
         args.named.isEmpty &&
-        ctorClass.enclosingLibrary.importUri.scheme == 'dart') {
+        ctorClass.enclosingLibrary.importUri.isScheme('dart')) {
       // Skip the slow SDK factory constructors when possible.
       switch (ctorClass.name) {
         case 'Map':
@@ -6308,7 +6308,7 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
       ]);
 
   bool _reifyFunctionType(FunctionNode f) {
-    if (_currentLibrary.importUri.scheme != 'dart') return true;
+    if (!_currentLibrary.importUri.isScheme('dart')) return true;
     var parent = f.parent;
 
     // SDK libraries can skip reification if they request it.
@@ -6337,7 +6337,7 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
   /// under which functions are compiled and exported.
   String _jsExportName(NamedNode n) {
     var library = getLibrary(n);
-    if (library == null || library.importUri.scheme != 'dart') return null;
+    if (library == null || !library.importUri.isScheme('dart')) return null;
 
     return _annotationName(n, isJSExportNameAnnotation);
   }
@@ -6363,7 +6363,7 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
   js_ast.Expression visitConstant(Constant node) {
     if (node is StaticTearOffConstant) {
       // JS() or external JS consts should not be lazily loaded.
-      var isSdk = node.target.enclosingLibrary.importUri.scheme == 'dart';
+      var isSdk = node.target.enclosingLibrary.importUri.isScheme('dart');
       if (_isInForeignJS) {
         return _emitStaticTarget(node.target);
       }

pkg/dev_compiler/lib/src/kernel/expression_compiler_worker.dart

@@ -299,7 +299,7 @@ class ExpressionCompilerWorker {
     var libraryUri = Uri.parse(request.libraryUri);
     var moduleName = request.moduleName;
 
-    if (libraryUri.scheme == 'dart') {
+    if (libraryUri.isScheme('dart')) {
       // compiling expressions inside the SDK currently fails because
       // SDK kernel outlines do not contain information that is needed
       // to detect the scope for expression evaluation - such as local
@@ -329,7 +329,7 @@ class ExpressionCompilerWorker {
     var originalComponent = _moduleCache.componentForModuleName[moduleName];
 
     var component = _sdkComponent;
-    if (libraryUri.scheme != 'dart') {
+    if (!libraryUri.isScheme('dart')) {
       _processedOptions.ticker.logMs('Collecting libraries for $moduleName');
 
       var libraries =

pkg/dev_compiler/lib/src/kernel/kernel_helpers.dart

@@ -92,7 +92,7 @@ bool isBuiltinAnnotation(
   var c = getAnnotationClass(value);
   if (c != null && c.name == className) {
     var uri = c.enclosingLibrary.importUri;
-    return uri.scheme == 'dart' && uri.path == libraryName;
+    return uri.isScheme('dart') && uri.path == libraryName;
   }
   return false;
 }
@@ -223,7 +223,7 @@ bool isCovariantField(Field f) {
 ///
 /// `dart:html` has many of these.
 bool isUnsupportedFactoryConstructor(Procedure node) {
-  if (node.name.isPrivate && node.enclosingLibrary.importUri.scheme == 'dart') {
+  if (node.name.isPrivate && node.enclosingLibrary.importUri.isScheme('dart')) {
     var body = node.function.body;
     if (body is Block) {
       var statements = body.statements;
@@ -365,4 +365,4 @@ bool _isNativeMarkerAnnotation(Expression annotation) {
 }
 
 bool _isDartInternal(Uri uri) =>
-    uri.scheme == 'dart' && uri.path == '_internal';
+    uri.isScheme('dart') && uri.path == '_internal';

pkg/dev_compiler/lib/src/kernel/native_types.dart

@@ -170,5 +170,5 @@ bool _isNativeAnnotation(Expression annotation) {
   var c = getAnnotationClass(annotation);
   return c != null &&
       (c.name == 'Native' || c.name == 'JsPeerInterface') &&
-      c.enclosingLibrary.importUri.scheme == 'dart';
+      c.enclosingLibrary.importUri.isScheme('dart');
 }

pkg/dev_compiler/lib/src/kernel/nullable_inference.dart

@@ -338,9 +338,9 @@ class NullableInference extends ExpressionVisitor<bool> {
 
   bool _isInternalSdkAnnotation(Library library) {
     var uri = library.importUri;
-    return uri.scheme == 'dart' && uri.pathSegments[0] == '_js_helper' ||
+    return uri.isScheme('dart') && uri.pathSegments[0] == '_js_helper' ||
         allowPackageMetaAnnotations &&
-            uri.scheme == 'package' &&
+            uri.isScheme('package') &&
             uri.pathSegments[0] == 'meta';
   }
 }

pkg/dev_compiler/lib/src/kernel/target.dart

@@ -120,11 +120,11 @@ class DevCompilerTarget extends Target {
   /// test framework.
   bool _allowedTestLibrary(Uri uri) {
     // Multi-root scheme used by modular test framework.
-    if (uri.scheme == 'dev-dart-app') return true;
+    if (uri.isScheme('dev-dart-app')) return true;
     return allowedNativeTest(uri);
   }
 
-  bool _allowedDartLibrary(Uri uri) => uri.scheme == 'dart';
+  bool _allowedDartLibrary(Uri uri) => uri.isScheme('dart');
 
   @override
   bool enableNative(Uri uri) =>

pkg/dev_compiler/test/expression_compiler/expression_compiler_test.dart

@@ -42,7 +42,7 @@ class Module {
 
   Module(this.importUri, this.fileUri)
       : name = libraryUriToJsIdentifier(importUri),
-        path = importUri.scheme == 'package'
+        path = importUri.isScheme('package')
             ? 'packages/${importUri.path}'
             : importUri.path;
 

pkg/dev_compiler/test/nullable_inference_test.dart

@@ -568,7 +568,7 @@ class _TestRecursiveVisitor extends RecursiveVisitor {
   void visitLibrary(Library node) {
     _staticTypeContext.enterLibrary(node);
     if (librariesFromDill.contains(node) ||
-        node.importUri.scheme == 'package' &&
+        node.importUri.isScheme('package') &&
             node.importUri.pathSegments[0] == 'meta') {
       return;
     }

pkg/front_end/lib/src/api_prototype/experimental_flags.dart

@@ -93,9 +93,9 @@ bool isExperimentEnabledInLibrary(ExperimentalFlag flag, Uri canonicalUri,
   if (!enabled!) {
     allowedExperimentalFlags ??= defaultAllowedExperimentalFlags;
     Set<ExperimentalFlag>? allowedFlags;
-    if (canonicalUri.scheme == 'dart') {
+    if (canonicalUri.isScheme('dart')) {
       allowedFlags = allowedExperimentalFlags.forSdkLibrary(canonicalUri.path);
-    } else if (canonicalUri.scheme == 'package') {
+    } else if (canonicalUri.isScheme('package')) {
       int index = canonicalUri.path.indexOf('/');
       String packageName;
       if (index >= 0) {
@@ -123,9 +123,9 @@ Version getExperimentEnabledVersionInLibrary(ExperimentalFlag flag,
   allowedExperimentalFlags ??= defaultAllowedExperimentalFlags;
 
   Set<ExperimentalFlag>? allowedFlags;
-  if (canonicalUri.scheme == 'dart') {
+  if (canonicalUri.isScheme('dart')) {
     allowedFlags = allowedExperimentalFlags.forSdkLibrary(canonicalUri.path);
-  } else if (canonicalUri.scheme == 'package') {
+  } else if (canonicalUri.isScheme('package')) {
     int index = canonicalUri.path.indexOf('/');
     String packageName;
     if (index >= 0) {
@@ -187,9 +187,9 @@ bool isExperimentEnabledInLibraryByVersion(
 
   Set<ExperimentalFlag>? allowedFlags;
   bool enabledByAllowed = false;
-  if (canonicalUri.scheme == 'dart') {
+  if (canonicalUri.isScheme('dart')) {
     allowedFlags = allowedExperimentalFlags.forSdkLibrary(canonicalUri.path);
-  } else if (canonicalUri.scheme == 'package') {
+  } else if (canonicalUri.isScheme('package')) {
     int index = canonicalUri.path.indexOf('/');
     String packageName;
     if (index >= 0) {

pkg/front_end/lib/src/api_prototype/language_version.dart

@@ -57,7 +57,7 @@ Future<VersionAndPackageUri> languageVersionForUri(
     UriTranslator uriTranslator = await context.options.getUriTranslator();
     Uri? fileUri;
     Package? package;
-    if (uri.scheme == "package") {
+    if (uri.isScheme("package")) {
       fileUri = uriTranslator.translate(uri);
       package = uriTranslator.getPackage(uri);
     } else {
@@ -65,8 +65,8 @@ Future<VersionAndPackageUri> languageVersionForUri(
       package = uriTranslator.packages.packageOf(uri);
     }
     Uri packageUri = uri;
-    if (packageUri.scheme != 'dart' &&
+    if (!packageUri.isScheme('dart') &&
-        packageUri.scheme != 'package' &&
+        !packageUri.isScheme('package') &&
         package != null &&
         // ignore: unnecessary_null_comparison
         package.name != null) {

pkg/front_end/lib/src/api_prototype/standard_file_system.dart

@@ -23,12 +23,12 @@ class StandardFileSystem implements FileSystem {
 
   @override
   FileSystemEntity entityForUri(Uri uri) {
-    if (uri.scheme == 'file') {
+    if (uri.isScheme('file')) {
       return new _IoFileSystemEntity(uri);
-    } else if (uri.scheme == '') {
+    } else if (!uri.hasScheme) {
       // TODO(askesc): Empty schemes should have been handled elsewhere.
       return new _IoFileSystemEntity(Uri.base.resolveUri(uri));
-    } else if (uri.scheme == 'data') {
+    } else if (uri.isScheme('data')) {
       return new DataFileSystemEntity(Uri.base.resolveUri(uri));
     } else {
       throw new FileSystemException(
@@ -125,7 +125,7 @@ class DataFileSystemEntity implements FileSystemEntity {
   final Uri uri;
 
   DataFileSystemEntity(this.uri)
-      : assert(uri.scheme == 'data'),
+      : assert(uri.isScheme('data')),
         assert(uri.data != null);
 
   @override

pkg/front_end/lib/src/base/processed_options.dart

@@ -563,7 +563,7 @@ class ProcessedOptions {
     }
 
     // When compiling the SDK the input files are normally `dart:` URIs.
-    if (inputs.every((uri) => uri.scheme == 'dart')) {
+    if (inputs.every((uri) => uri.isScheme('dart'))) {
       return _packages = PackageConfig.empty;
     }
 
@@ -577,7 +577,7 @@ class ProcessedOptions {
 
     Uri input = inputs.first;
 
-    if (input.scheme == 'package') {
+    if (input.isScheme('package')) {
       report(
           messageCantInferPackagesFromPackageUri.withLocation(
               input, -1, noLength),

pkg/front_end/lib/src/compute_platform_binaries_location.dart

@@ -95,7 +95,7 @@ Uri computePlatformBinariesLocation({bool forceBuildDir: false}) {
 /// Translates an SDK URI ("org-dartlang-sdk:///...") to a file URI.
 Uri translateSdk(Uri uri) {
   if (CompilerContext.isActive) {
-    if (uri.scheme == "org-dartlang-sdk") {
+    if (uri.isScheme("org-dartlang-sdk")) {
       String path = uri.path;
       if (path.startsWith("/sdk/")) {
         CompilerContext context = CompilerContext.current;
@@ -148,7 +148,7 @@ Uri translateSdk(Uri uri) {
 }
 
 bool isExistingFile(Uri uri) {
-  if (uri.scheme == "file") {
+  if (uri.isScheme("file")) {
     return new File.fromUri(uri).existsSync();
   } else {
     return false;

pkg/front_end/lib/src/fasta/builder/class_builder.dart

@@ -326,7 +326,7 @@ abstract class ClassBuilderImpl extends DeclarationBuilderImpl
     }
     if (name == "FutureOr") {
       LibraryBuilder parentLibrary = parent as LibraryBuilder;
-      if (parentLibrary.importUri.scheme == "dart" &&
+      if (parentLibrary.importUri.isScheme("dart") &&
           parentLibrary.importUri.path == "async") {
         assert(arguments != null && arguments.length == 1);
         return new FutureOrType(arguments!.single, nullability);

pkg/front_end/lib/src/fasta/compiler_context.dart

@@ -86,7 +86,7 @@ class CompilerContext {
   }
 
   static void recordDependency(Uri uri) {
-    if (uri.scheme != "file" && uri.scheme != "http") {
+    if (!uri.isScheme("file") && !uri.isScheme("http")) {
       throw new ArgumentError("Expected a file or http URI, but got: '$uri'.");
     }
     CompilerContext? context = Zone.current[compilerContextKey];

pkg/front_end/lib/src/fasta/dill/dill_loader.dart

@@ -120,7 +120,7 @@ class DillLoader extends Loader {
       assert(libraryBuilder != null, "No library found for $uri.");
       _builders[uri] = libraryBuilder!;
       assert(libraryBuilder.loader == this);
-      if (uri.scheme == "dart") {
+      if (uri.isScheme("dart")) {
         if (uri.path == "core") {
           _coreLibrary = libraryBuilder;
         }
@@ -352,7 +352,7 @@ severity: $severity
   void registerLibraryBuilder(DillLibraryBuilder libraryBuilder) {
     Uri importUri = libraryBuilder.importUri;
     libraryBuilder.loader = this;
-    if (importUri.scheme == "dart" && importUri.path == "core") {
+    if (importUri.isScheme("dart") && importUri.path == "core") {
       _coreLibrary = libraryBuilder;
     }
     _builders[importUri] = libraryBuilder;

pkg/front_end/lib/src/fasta/hybrid_file_system.dart

@@ -37,7 +37,7 @@ class HybridFileSystemEntity implements FileSystemEntity {
   Future<FileSystemEntity> get delegate async {
     if (_delegate != null) return _delegate!;
     FileSystemEntity entity = _fs.memory.entityForUri(uri);
-    if (((uri.scheme != 'file' && uri.scheme != 'data') &&
+    if (((!uri.isScheme('file') && !uri.isScheme('data')) &&
             _fs.physical is StandardFileSystem) ||
         await entity.exists()) {
       _delegate = entity;

pkg/front_end/lib/src/fasta/incremental_compiler.dart

@@ -1272,7 +1272,7 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
       _platformBuilders = <LibraryBuilder>[];
       for (DillLibraryBuilder builder
           in dillLoadedData.loader.libraryBuilders) {
-        if (builder.importUri.scheme == "dart") {
+        if (builder.importUri.isScheme("dart")) {
           _platformBuilders!.add(builder);
         } else {
           _userBuilders![builder.importUri] = builder;
@@ -1425,7 +1425,7 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
         _platformBuilders = <LibraryBuilder>[];
         for (DillLibraryBuilder builder
             in _dillLoadedData!.loader.libraryBuilders) {
-          if (builder.importUri.scheme == "dart") {
+          if (builder.importUri.isScheme("dart")) {
             _platformBuilders!.add(builder);
           } else {
             _userBuilders![builder.importUri] = builder;
@@ -1492,7 +1492,7 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
           partUriToLibraryImportUri[partUri] = library.importUri;
         }
       }
-      if (library.importUri.scheme == "dart") {
+      if (library.importUri.isScheme("dart")) {
         result.add(library);
         inputLibrariesFiltered?.add(library);
       } else {
@@ -1501,7 +1501,7 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
       }
     }
     for (LibraryBuilder libraryBuilder in reusedLibraries) {
-      if (libraryBuilder.importUri.scheme == "dart" &&
+      if (libraryBuilder.importUri.isScheme("dart") &&
           !libraryBuilder.isSynthetic) {
         continue;
       }
@@ -1550,7 +1550,7 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
     List<Library> removedLibraries = <Library>[];
     bool removedDillBuilders = false;
     for (Uri uri in potentiallyReferencedLibraries.keys) {
-      if (uri.scheme == "package") continue;
+      if (uri.isScheme("package")) continue;
       LibraryBuilder? builder =
           currentKernelTarget.loader.deregisterLibraryBuilder(uri);
       if (builder != null) {
@@ -1913,7 +1913,7 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
       if (importUri != fileUri && invalidatedUris.contains(fileUri)) {
         return true;
       }
-      if (_hasToCheckPackageUris && importUri.scheme == "package") {
+      if (_hasToCheckPackageUris && importUri.isScheme("package")) {
         // Get package name, check if the base URI has changed for the package,
         // if it has, translate the URI again,
         // otherwise the URI cannot have changed.
@@ -1935,7 +1935,7 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
     }
 
     void addBuilderAndInvalidateUris(Uri uri, LibraryBuilder libraryBuilder) {
-      if (uri.scheme == "dart" && !libraryBuilder.isSynthetic) {
+      if (uri.isScheme("dart") && !libraryBuilder.isSynthetic) {
         if (seenUris.add(libraryBuilder.importUri)) {
           reusedLibraries.add(libraryBuilder);
         }
@@ -2355,7 +2355,7 @@ class _InitializationFromComponent extends _InitializationStrategy {
     bool foundDartCore = false;
     for (int i = 0; i < component.libraries.length; i++) {
       Library library = component.libraries[i];
-      if (library.importUri.scheme == "dart" &&
+      if (library.importUri.isScheme("dart") &&
           library.importUri.path == "core") {
         foundDartCore = true;
         break;
@@ -2501,7 +2501,7 @@ class _InitializationFromUri extends _InitializationFromSdkSummary {
         // (e.g. the package still exists and hasn't been updated).
         // Also verify NNBD settings.
         for (Library lib in data.component!.libraries) {
-          if (lib.importUri.scheme == "package" &&
+          if (lib.importUri.isScheme("package") &&
               uriTranslator.translate(lib.importUri, false) != lib.fileUri) {
             // Package has been removed or updated.
             // This library should be thrown away.
@@ -2649,7 +2649,7 @@ class _ComponentProblems {
 extension on UriTranslator {
   Uri? getPartFileUri(Uri parentFileUri, LibraryPart part) {
     Uri? fileUri = getPartUri(parentFileUri, part);
-    if (fileUri.scheme == "package") {
+    if (fileUri.isScheme("package")) {
       // Part was specified via package URI and the resolve above thus
       // did not go as expected. Translate the package URI to get the
       // actual file URI.

pkg/front_end/lib/src/fasta/incremental_serializer.dart

@@ -43,7 +43,7 @@ class IncrementalSerializer {
         Uri uri = lib.importUri;
         // Uris need to be unique.
         if (!uris.add(lib.fileUri)) return false;
-        if (uri.scheme == "package") {
+        if (uri.isScheme("package")) {
           String thisPackageName = uri.pathSegments.first;
           if (packageName == null) {
             packageName = thisPackageName;
@@ -117,7 +117,7 @@ class IncrementalSerializer {
     List<Library> nonPackageLibraries = <Library>[];
     for (Library lib in component.libraries) {
       Uri uri = lib.importUri;
-      if (uri.scheme == "package") {
+      if (uri.isScheme("package")) {
         packageLibraries.add(lib);
       } else {
         nonPackageLibraries.add(lib);
@@ -179,7 +179,7 @@ class IncrementalSerializer {
     for (Library lib in component.libraries) {
       for (LibraryDependency dependency in lib.dependencies) {
         if (!got.contains(dependency.targetLibrary)) {
-          if (dependency.targetLibrary.importUri.scheme == "dart") {
+          if (dependency.targetLibrary.importUri.isScheme("dart")) {
             continue;
           }
           return false;
@@ -241,7 +241,7 @@ class IncrementalSerializer {
     for (Library lib in libraries) {
       for (LibraryDependency dep in lib.dependencies) {
         Library dependencyLibrary = dep.importedLibraryReference.asLibrary;
-        if (dependencyLibrary.importUri.scheme != "package") continue;
+        if (!dependencyLibrary.importUri.isScheme("package")) continue;
         Uri dependencyLibraryUri =
             dep.importedLibraryReference.asLibrary.fileUri;
         SerializationGroup? depGroup = uriToGroup[dependencyLibraryUri];

pkg/front_end/lib/src/fasta/kernel/body_builder.dart

@@ -355,7 +355,7 @@ class BodyBuilder extends ScopeListener<JumpTarget>
         stringExpectedAfterNative = libraryBuilder
             .loader.target.backendTarget.nativeExtensionExpectsString,
         ignoreMainInGetMainClosure =
-            libraryBuilder.importUri.scheme == 'dart' &&
+            libraryBuilder.importUri.isScheme('dart') &&
                 (libraryBuilder.importUri.path == "_builtin" ||
                     libraryBuilder.importUri.path == "ui"),
         needsImplicitSuperInitializer =

pkg/front_end/lib/src/fasta/kernel/constant_evaluator.dart

@@ -965,7 +965,7 @@ class ConstantEvaluator implements ExpressionVisitor<Constant> {
   Map<String, String> _computeSupportedLibraries() {
     Map<String, String> map = {};
     for (Library library in component.libraries) {
-      if (library.importUri.scheme == 'dart') {
+      if (library.importUri.isScheme('dart')) {
         map[library.importUri.path] =
             DartLibrarySupport.getDartLibrarySupportValue(
                 library.importUri.path,

pkg/front_end/lib/src/fasta/kernel/kernel_target.dart

@@ -1667,7 +1667,7 @@ class KernelTarget extends TargetImplementation {
   }
 
   void readPatchFiles(SourceLibraryBuilder library) {
-    assert(library.importUri.scheme == "dart");
+    assert(library.importUri.isScheme("dart"));
     List<Uri>? patches = uriTranslator.getDartPatches(library.importUri.path);
     if (patches != null) {
       SourceLibraryBuilder? first;

pkg/front_end/lib/src/fasta/kernel/type_labeler.dart

@@ -66,7 +66,7 @@ class TypeLabeler implements DartTypeVisitor<void>, ConstantVisitor<void> {
   static bool isObject(DartType type) {
     if (type is InterfaceType && type.classNode.name == 'Object') {
       Uri importUri = type.classNode.enclosingLibrary.importUri;
-      return importUri.scheme == 'dart' && importUri.path == 'core';
+      return importUri.isScheme('dart') && importUri.path == 'core';
     }
     return false;
   }
@@ -504,7 +504,7 @@ class LabeledNode {
   }
 
   String get originMessage {
-    if (importUri.scheme == 'dart' && importUri.path == 'core') {
+    if (importUri.isScheme('dart') && importUri.path == 'core') {
       if (node is Class && denylistedCoreClasses.contains(name)) {
         // Denylisted core class. Only print if ambiguous.
         List<LabeledNode> entityForName = typeLabeler.nameMap[name]!;
@@ -521,7 +521,7 @@ class LabeledNode {
         return "";
       }
     }
-    Message message = (importUri == fileUri || importUri.scheme == 'dart')
+    Message message = (importUri == fileUri || importUri.isScheme('dart'))
         ? templateTypeOrigin.withArguments(toString(), importUri)
         : templateTypeOriginWithFileUri.withArguments(
             toString(), importUri, fileUri);

pkg/front_end/lib/src/fasta/kernel/verifier.dart

@@ -241,7 +241,7 @@ class FastaVerifyingVisitor extends VerifyingVisitor {
     // 'dart:test' is used in the unit tests and isn't an actual part of the
     // platform.
     if (skipPlatform &&
-        node.importUri.scheme == 'dart' &&
+        node.importUri.isScheme('dart') &&
         node.importUri.path != 'test') {
       return;
     }
@@ -304,7 +304,7 @@ class FastaVerifyingVisitor extends VerifyingVisitor {
 
   bool isObjectClass(Class c) {
     return c.name == "Object" &&
-        c.enclosingLibrary.importUri.scheme == "dart" &&
+        c.enclosingLibrary.importUri.isScheme("dart") &&
         c.enclosingLibrary.importUri.path == "core";
   }
 
@@ -435,7 +435,7 @@ class FastaVerifyingVisitor extends VerifyingVisitor {
   }
 
   void _checkConstructorTearOff(Node node, Member tearOffTarget) {
-    if (tearOffTarget.enclosingLibrary.importUri.scheme == 'dart') {
+    if (tearOffTarget.enclosingLibrary.importUri.isScheme('dart')) {
       // Platform libraries are not compilation with test flags and might
       // contain tear-offs not expected when testing lowerings.
       return;
@@ -540,7 +540,7 @@ class FastaVerifyGetStaticType extends VerifyGetStaticType {
     // 'dart:test' is used in the unit tests and isn't an actual part of the
     // platform.
     if (skipPlatform &&
-        node.importUri.scheme == 'dart' &&
+        node.importUri.isScheme('dart') &&
         node.importUri.path != "test") {
       return;
     }

pkg/front_end/lib/src/fasta/source/source_class_builder.dart

@@ -714,7 +714,7 @@ class SourceClassBuilder extends ClassBuilderImpl
                 this.charOffset,
                 noLength);
           } else if (interface.cls.name == "FutureOr" &&
-              interface.cls.enclosingLibrary.importUri.scheme == "dart" &&
+              interface.cls.enclosingLibrary.importUri.isScheme("dart") &&
               interface.cls.enclosingLibrary.importUri.path == "async") {
             addProblem(messageImplementsFutureOr, this.charOffset, noLength);
           } else if (implemented.contains(interface)) {

pkg/front_end/lib/src/fasta/source/source_library_builder.dart

@@ -289,12 +289,12 @@ class SourceLibraryBuilder extends LibraryBuilderImpl {
             new Scope.top()) {
     assert(
         _packageUri == null ||
-            importUri.scheme != 'package' ||
+            !importUri.isScheme('package') ||
             importUri.path.startsWith(_packageUri!.path),
         "Foreign package uri '$_packageUri' set on library with import uri "
         "'${importUri}'.");
     assert(
-        importUri.scheme != 'dart' || _packageUri == null,
+        !importUri.isScheme('dart') || _packageUri == null,
         "Package uri '$_packageUri' set on dart: library with import uri "
         "'${importUri}'.");
   }
@@ -638,7 +638,7 @@ class SourceLibraryBuilder extends LibraryBuilderImpl {
     return previous;
   }
 
-  bool uriIsValid(Uri uri) => uri.scheme != MALFORMED_URI_SCHEME;
+  bool uriIsValid(Uri uri) => !uri.isScheme(MALFORMED_URI_SCHEME);
 
   Uri resolve(Uri baseUri, String? uri, int uriOffset, {isPart: false}) {
     if (uri == null) {
@@ -657,7 +657,7 @@ class SourceLibraryBuilder extends LibraryBuilderImpl {
       return new Uri(
           scheme: MALFORMED_URI_SCHEME, query: Uri.encodeQueryComponent(uri));
     }
-    if (isPart && baseUri.scheme == "dart") {
+    if (isPart && baseUri.isScheme("dart")) {
       // Resolve using special rules for dart: URIs
       return resolveRelativeUri(baseUri, parsedUri);
     } else {
@@ -1668,7 +1668,7 @@ class SourceLibraryBuilder extends LibraryBuilderImpl {
     if (className != "Function") {
       return;
     }
-    if (decType == "class" && importUri.scheme == "dart") {
+    if (decType == "class" && importUri.isScheme("dart")) {
       // Allow declaration of class Function in the sdk.
       return;
     }
@@ -3158,9 +3158,9 @@ class SourceLibraryBuilder extends LibraryBuilderImpl {
         preferred = declaration;
       } else if (other is LoadLibraryBuilder) {
         preferred = other;
-      } else if (otherUri.scheme == "dart" && uri.scheme != "dart") {
+      } else if (otherUri.isScheme("dart") && !uri.isScheme("dart")) {
         preferred = declaration;
-      } else if (uri.scheme == "dart" && otherUri.scheme != "dart") {
+      } else if (uri.isScheme("dart") && !otherUri.isScheme("dart")) {
         preferred = other;
       }
     }
@@ -3901,7 +3901,7 @@ class SourceLibraryBuilder extends LibraryBuilderImpl {
   }
 
   void exportMemberFromPatch(String name, Builder member) {
-    if (importUri.scheme != "dart" || !importUri.path.startsWith("_")) {
+    if (!importUri.isScheme("dart") || !importUri.path.startsWith("_")) {
       addProblem(templatePatchInjectionFailed.withArguments(name, importUri),
           member.charOffset, noLength, member.fileUri);
     }

pkg/front_end/lib/src/fasta/source/source_loader.dart

@@ -265,7 +265,7 @@ class SourceLoader extends Loader {
 
   void registerLibraryBuilder(LibraryBuilder libraryBuilder) {
     Uri uri = libraryBuilder.importUri;
-    if (uri.scheme == "dart" && uri.path == "core") {
+    if (uri.isScheme("dart") && uri.path == "core") {
       _coreLibrary = libraryBuilder;
     }
     _builders[uri] = libraryBuilder;
@@ -326,7 +326,7 @@ class SourceLoader extends Loader {
         referencesFrom: referencesFrom,
         referenceIsPartOwner: referenceIsPartOwner,
         isUnsupported: origin?.library.isUnsupported ??
-            importUri.scheme == 'dart' &&
+            importUri.isScheme('dart') &&
                 !target.uriTranslator.isLibrarySupported(importUri.path));
   }
 
@@ -359,9 +359,9 @@ class SourceLoader extends Loader {
       Library? referencesFrom,
       bool? referenceIsPartOwner) {
     if (fileUri != null &&
-        (fileUri.scheme == "dart" ||
+        (fileUri.isScheme("dart") ||
-            fileUri.scheme == "package" ||
+            fileUri.isScheme("package") ||
-            fileUri.scheme == "dart-ext")) {
+            fileUri.isScheme("dart-ext"))) {
       fileUri = null;
     }
     package_config.Package? packageForLanguageVersion;
@@ -373,7 +373,7 @@ class SourceLoader extends Loader {
               new Uri(
                   scheme: untranslatableUriScheme,
                   path: Uri.encodeComponent("$uri"));
-          if (uri.scheme == "package") {
+          if (uri.isScheme("package")) {
             packageForLanguageVersion = target.uriTranslator.getPackage(uri);
           } else {
             packageForLanguageVersion =
@@ -396,8 +396,8 @@ class SourceLoader extends Loader {
     Message? packageLanguageVersionProblem;
     if (packageForLanguageVersion != null) {
       Uri importUri = origin?.importUri ?? uri;
-      if (importUri.scheme != 'dart' &&
+      if (!importUri.isScheme('dart') &&
-          importUri.scheme != 'package' &&
+          !importUri.isScheme('package') &&
           // ignore: unnecessary_null_comparison
           packageForLanguageVersion.name != null) {
         packageUri =
@@ -455,7 +455,7 @@ class SourceLoader extends Loader {
     if (target.backendTarget.mayDefineRestrictedType(libraryUri)) {
       libraryBuilder.mayImplementRestrictedTypes = true;
     }
-    if (uri.scheme == "dart") {
+    if (uri.isScheme("dart")) {
       target.readPatchFiles(libraryBuilder);
     }
     _unparsedLibraries.addLast(libraryBuilder);
@@ -516,7 +516,7 @@ class SourceLoader extends Loader {
   }
 
   void _checkForDartCore(Uri uri, LibraryBuilder libraryBuilder) {
-    if (uri.scheme == "dart") {
+    if (uri.isScheme("dart")) {
       if (uri.path == "core") {
         _coreLibrary = libraryBuilder;
       } else if (uri.path == "typed_data") {
@@ -595,7 +595,7 @@ class SourceLoader extends Loader {
   }
 
   bool _hasLibraryAccess({required Uri imported, required Uri? importer}) {
-    if (imported.scheme == "dart" && imported.path.startsWith("_")) {
+    if (imported.isScheme("dart") && imported.path.startsWith("_")) {
       if (importer == null) {
         return false;
       } else {
@@ -810,7 +810,7 @@ severity: $severity
 
     if (bytes == null) {
       // Error recovery.
-      if (fileUri.scheme == untranslatableUriScheme) {
+      if (fileUri.isScheme(untranslatableUriScheme)) {
         Message message =
             templateUntranslatableUri.withArguments(library.importUri);
         library.addProblemAtAccessors(message);
@@ -820,7 +820,7 @@ severity: $severity
             templateInternalProblemUriMissingScheme.withArguments(fileUri),
             -1,
             library.importUri);
-      } else if (fileUri.scheme == SourceLibraryBuilder.MALFORMED_URI_SCHEME) {
+      } else if (fileUri.isScheme(SourceLibraryBuilder.MALFORMED_URI_SCHEME)) {
         library.addProblemAtAccessors(messageExpectedUri);
         bytes = synthesizeSourceForMissingFile(library.importUri, null);
       }
@@ -1027,7 +1027,7 @@ severity: $severity
           continue;
         }
       }
-      if (libraryBuilder.importUri.scheme == 'package') {
+      if (libraryBuilder.importUri.isScheme('package')) {
         (libraryByPackage[null] ??= []).add(libraryBuilder);
       } else {
         if (emitNonPackageErrors) {
@@ -1965,7 +1965,7 @@ severity: $severity
     for (LibraryBuilder libraryBuilder in libraryBuilders) {
       if (!libraryBuilder.isPatch &&
           (libraryBuilder.loader == this ||
-              libraryBuilder.importUri.scheme == "dart" ||
+              libraryBuilder.importUri.isScheme("dart") ||
               libraryBuilder == this.first)) {
         if (libraries.add(libraryBuilder.library)) {
           workList.add(libraryBuilder.library);

pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart

@@ -1064,7 +1064,7 @@ class TypeInferrerImpl implements TypeInferrer {
               onType,
               onTypeInstantiateToBounds,
               target,
-              isPlatform: extensionBuilder.library.importUri.scheme == 'dart');
+              isPlatform: extensionBuilder.library.importUri.isScheme('dart'));
           if (noneMoreSpecific.isNotEmpty) {
             bool isMostSpecific = true;
             for (ExtensionAccessCandidate other in noneMoreSpecific) {

pkg/front_end/lib/src/fasta/type_inference/type_schema_elimination.dart

@@ -70,7 +70,7 @@ class _TypeSchemaEliminationVisitor extends ReplacementVisitor {
     assert(topType == const DynamicType() ||
         topType is InterfaceType &&
             topType.nullability == Nullability.nullable &&
-            topType.classNode.enclosingLibrary.importUri.scheme == "dart" &&
+            topType.classNode.enclosingLibrary.importUri.isScheme("dart") &&
             topType.classNode.enclosingLibrary.importUri.path == "core" &&
             topType.classNode.name == "Object");
     assert(

pkg/front_end/lib/src/fasta/uri_translator.dart

@@ -22,7 +22,7 @@ class UriTranslator {
       dartLibraries.libraryInfoFor(libraryName)?.patches;
 
   bool isPlatformImplementation(Uri uri) {
-    if (uri.scheme != "dart") return false;
+    if (!uri.isScheme("dart")) return false;
     String path = uri.path;
     return dartLibraries.libraryInfoFor(path) == null || path.startsWith("_");
   }
@@ -31,8 +31,8 @@ class UriTranslator {
   // callback, so we can provide an error location when one is available. For
   // example, if the error occurs in an `import`.
   Uri? translate(Uri uri, [bool reportMessage = true]) {
-    if (uri.scheme == "dart") return _translateDartUri(uri);
+    if (uri.isScheme("dart")) return _translateDartUri(uri);
-    if (uri.scheme == "package") {
+    if (uri.isScheme("package")) {
       return _translatePackageUri(uri, reportMessage);
     }
     return null;
@@ -42,7 +42,7 @@ class UriTranslator {
   Package? getPackage(Uri uri) {
     // ignore: unnecessary_null_comparison
     if (packages == null) return null;
-    if (uri.scheme != "package") return null;
+    if (!uri.isScheme("package")) return null;
     int firstSlash = uri.path.indexOf('/');
     if (firstSlash == -1) return null;
     String packageName = uri.path.substring(0, firstSlash);

pkg/front_end/lib/src/fasta/util/outline_extractor.dart

@@ -116,7 +116,7 @@ class _Processor {
   Future<TopLevel> preprocessUri(Uri importUri, {Uri? partOf}) async {
     if (verbosityLevel >= 20) log("$importUri =>");
     Uri fileUri = importUri;
-    if (importUri.scheme == "package") {
+    if (importUri.isScheme("package")) {
       fileUri = uriTranslator.translate(importUri)!;
     }
     if (verbosityLevel >= 20) log("$fileUri");
@@ -202,14 +202,14 @@ class _Processor {
       worklist.add(new _TopLevelAndAstNode(entrypointish, child));
 
       if (child is Part) {
-        if (child.uri.scheme != "dart") {
+        if (!child.uri.isScheme("dart")) {
           TopLevel partTopLevel = parsed[child.uri] ??
               await preprocessUri(child.uri, partOf: entrypointish.uri);
           await _premarkTopLevel(worklist, closed, partTopLevel);
         }
       } else if (child is Export) {
         for (Uri importedUri in child.uris) {
-          if (importedUri.scheme != "dart") {
+          if (!importedUri.isScheme("dart")) {
             TopLevel exportTopLevel =
                 parsed[importedUri] ?? await preprocessUri(importedUri);
             await _premarkTopLevel(worklist, closed, exportTopLevel);
@@ -230,7 +230,7 @@ class _Processor {
         if (child is Import) {
           child.marked = Coloring.Marked;
           for (Uri importedUri in child.uris) {
-            if (importedUri.scheme != "dart") {
+            if (!importedUri.isScheme("dart")) {
               TopLevel importedTopLevel =
                   parsed[importedUri] ?? await preprocessUri(importedUri);
               imported.add(importedTopLevel);
@@ -238,7 +238,7 @@ class _Processor {
           }
         } else if (child is PartOf) {
           child.marked = Coloring.Marked;
-          if (child.partOfUri.scheme != "dart") {
+          if (!child.partOfUri.isScheme("dart")) {
             TopLevel part = parsed[child.partOfUri]!;
             List<TopLevel> importsFromPart =
                 await _preprocessImportsAsNeeded(imports, part);
@@ -392,7 +392,7 @@ class _Processor {
           if (child is Part) {
             child.marked = Coloring.Marked;
             // do stuff to part.
-            if (child.uri.scheme != "dart") {
+            if (!child.uri.isScheme("dart")) {
               other = parsed[child.uri] ??
                   await preprocessUri(child.uri, partOf: topLevel.uri);
             }
@@ -400,7 +400,7 @@ class _Processor {
             child.marked = Coloring.Marked;
             // do stuff to export.
             for (Uri importedUri in child.uris) {
-              if (importedUri.scheme != "dart") {
+              if (!importedUri.isScheme("dart")) {
                 other = parsed[importedUri] ?? await preprocessUri(importedUri);
               }
             }
@@ -468,7 +468,7 @@ class _Processor {
           }
           if (child is Import) {
             for (Uri importedUri in child.uris) {
-              if (importedUri.scheme != "dart") {
+              if (!importedUri.isScheme("dart")) {
                 imported.add(importedUri);
               }
             }
@@ -478,7 +478,7 @@ class _Processor {
       if (sb.isNotEmpty) count++;
       Uri uri = entry.key;
       Uri fileUri = uri;
-      if (uri.scheme == "package") {
+      if (uri.isScheme("package")) {
         fileUri = uriTranslator.translate(uri)!;
       }
       result[fileUri] = sb.toString();
@@ -489,7 +489,7 @@ class _Processor {
       // uri imports a file we haven't read. Check if it exists and include it
       // as an empty file if it does.
       Uri fileUri = uri;
-      if (uri.scheme == "package") {
+      if (uri.isScheme("package")) {
         fileUri = uriTranslator.translate(uri)!;
       }
       if (await fileSystem.entityForUri(fileUri).exists()) {

pkg/front_end/lib/src/testing/compiler_common.dart

@@ -140,7 +140,7 @@ String _invalidLibrariesSpec = '''
 ''';
 
 bool isDartCoreLibrary(Library lib) => isDartCore(lib.importUri);
-bool isDartCore(Uri uri) => uri.scheme == 'dart' && uri.path == 'core';
+bool isDartCore(Uri uri) => uri.isScheme('dart') && uri.path == 'core';
 
 /// Find a library in [component] whose Uri ends with the given [suffix]
 Library findLibrary(Component component, String suffix) {

pkg/front_end/lib/src/testing/id_testing_helper.dart

@@ -451,8 +451,8 @@ Future<TestResult<T>> runTestForConfig<T>(
 
   bool excludeLibrary(Library library) {
     return forUserLibrariesOnly &&
-        (library.importUri.scheme == 'dart' ||
+        (library.importUri.isScheme('dart') ||
-            library.importUri.scheme == 'package');
+            library.importUri.isScheme('package'));
   }
 
   await dataComputer.inspectTestResultData(testResultData);

pkg/front_end/test/ast_nodes_has_to_string_test.dart

@@ -55,7 +55,7 @@ Future<void> main(List<String> args) async {
               .where((Member m) =>
                   !m.isAbstract &&
                   m.name.text == "toString" &&
-                  m.enclosingLibrary.importUri.scheme != "dart")
+                  !m.enclosingLibrary.importUri.isScheme("dart"))
               .toList();
           if (toStringList.length > 1) throw "What?";
           if (toStringList.length == 1) {
@@ -157,7 +157,7 @@ Future<void> main(List<String> args) async {
             .where((Member m) =>
                 !m.isAbstract &&
                 m.name.text == "toString" &&
-                m.enclosingLibrary.importUri.scheme != "dart")
+                !m.enclosingLibrary.importUri.isScheme("dart"))
             .toList();
         Member toString = toStringList.single;
         if (toString.fileUri != uri) continue;

pkg/front_end/test/comments_on_certain_arguments_tool.dart

@@ -88,7 +88,7 @@ Future<void> main(List<String> args) async {
   component = incrementalCompilerResult.component;
 
   for (Library library in component.libraries) {
-    if (library.importUri.scheme == "dart") continue;
+    if (library.importUri.isScheme("dart")) continue;
     // This isn't perfect because of parts, but (for now) it'll do.
     for (Uri uri in libUris) {
       if (library.fileUri.toString().startsWith(uri.toString())) {

pkg/front_end/test/compile_benchmark.dart

@@ -363,7 +363,7 @@ class RegisterCallTransformer extends RecursiveVisitor {
 
   @override
   void visitLibrary(Library node) {
-    if (node.importUri.scheme == "package" &&
+    if (node.importUri.isScheme("package") &&
         node.importUri.pathSegments.first == "front_end") {
       super.visitLibrary(node);
     }
@@ -395,7 +395,7 @@ class RegisterTimeTransformer extends RecursiveVisitor {
 
   @override
   void visitLibrary(Library node) {
-    if (node.importUri.scheme == "package" &&
+    if (node.importUri.isScheme("package") &&
         node.importUri.pathSegments.first == "front_end") {
       super.visitLibrary(node);
     }

pkg/front_end/test/crashing_test_case_minimizer_impl.dart

@@ -778,9 +778,9 @@ worlds:
   void _rewriteImportsExportsToUriInternal(
       Token uriToken, Uri oldUri, List<_Replacement> replacements, Uri newUri) {
     Uri tokenUri = _getUri(uriToken, oldUri, resolvePackage: false);
-    if (tokenUri.scheme == "package" || tokenUri.scheme == "dart") return;
+    if (tokenUri.isScheme("package") || tokenUri.isScheme("dart")) return;
     Uri asPackageUri = _getImportUri(tokenUri);
-    if (asPackageUri.scheme == "package") {
+    if (asPackageUri.isScheme("package")) {
       // Just replace with this package uri.
       replacements.add(new _Replacement(
         uriToken.offset - 1,
@@ -803,7 +803,7 @@ worlds:
     String uriString = uriToken.lexeme;
     uriString = uriString.substring(1, uriString.length - 1);
     Uri uriTokenUri = uri.resolve(uriString);
-    if (resolvePackage && uriTokenUri.scheme == "package") {
+    if (resolvePackage && uriTokenUri.isScheme("package")) {
       Package package = _latestCrashingIncrementalCompiler!
           .getPackageForPackageName(uriTokenUri.pathSegments.first)!;
       uriTokenUri = package.packageUriRoot

pkg/front_end/test/enable_non_nullable/enable_non_nullable_test.dart

@@ -116,7 +116,7 @@ Future<void> test(
   Expect.isFalse(
       hadDiagnostic, "Compilation had diagnostics (errors, warnings)!");
   for (Library library in result.component!.libraries) {
-    if (library.importUri.scheme != 'dart') {
+    if (!library.importUri.isScheme('dart')) {
       bool usesLegacy =
           await uriUsesLegacyLanguageVersion(library.fileUri, options);
       VersionAndPackageUri versionAndPackageUri =
@@ -143,7 +143,7 @@ Future<void> test(
           "Expected library ${library.importUri} with version "
           "${library.languageVersion} to be opted in.");
       Expect.isTrue(
-          versionAndPackageUri.packageUri.scheme != 'package' ||
+          !versionAndPackageUri.packageUri.isScheme('package') ||
               !versionAndPackageUri.packageUri.path
                   .startsWith('allowed_package') ||
               library.languageVersion < versionOptsInAllowed ||

pkg/front_end/test/fasta/testing/suite.dart

@@ -598,7 +598,7 @@ class FastaContext extends ChainContext with MatchContext {
         }
         for (String argument in parsedOptions.arguments) {
           Uri uri = description.uri.resolve(argument);
-          if (uri.scheme != 'package') {
+          if (!uri.isScheme('package')) {
             File f = new File.fromUri(uri);
             if (!f.existsSync()) {
               throw new UnsupportedError("No file found: $f ($argument)");
@@ -1328,11 +1328,11 @@ class FuzzCompiles
     Map<Uri, LibraryBuilder> builders = {};
     for (LibraryBuilder builder
         in incrementalCompiler.kernelTargetForTesting!.loader.libraryBuilders) {
-      if (builder.importUri.scheme == "dart" && !builder.isSynthetic) continue;
+      if (builder.importUri.isScheme("dart") && !builder.isSynthetic) continue;
       builders[builder.fileUri] = builder;
       for (LibraryPart part in builder.library.parts) {
         Uri thisPartUri = builder.importUri.resolve(part.partUri);
-        if (thisPartUri.scheme == "package") {
+        if (thisPartUri.isScheme("package")) {
           thisPartUri = incrementalCompiler
               .kernelTargetForTesting!.uriTranslator
               .translate(thisPartUri)!;
@@ -1761,8 +1761,8 @@ Set<Uri> createUserLibrariesImportUriSet(
       component.libraries.map((Library library) => library.importUri).toSet();
   Set<Uri> userLibraries = component.libraries
       .where((Library library) =>
-          library.importUri.scheme != 'dart' &&
+          !library.importUri.isScheme('dart') &&
-          library.importUri.scheme != 'package' &&
+          !library.importUri.isScheme('package') &&
           !excludedLibraries.contains(library))
       .map((Library library) => library.importUri)
       .toSet();
@@ -2171,7 +2171,7 @@ class MatchHierarchy
       ComponentResult result, FastaContext context) {
     Component component = result.component;
     Uri uri =
-        component.uriToSource.keys.firstWhere((uri) => uri.scheme == "file");
+        component.uriToSource.keys.firstWhere((uri) => uri.isScheme("file"));
     KernelTarget target = result.sourceTarget;
     ClassHierarchyBuilder hierarchy = target.loader.hierarchyBuilder;
     StringBuffer sb = new StringBuffer();

pkg/front_end/test/fasta/type_inference/type_constraint_gatherer_nnbd_test.dart

@@ -48,13 +48,13 @@ class TypeConstraintGathererTest {
         "the core library and the test library.");
     Library firstLibrary = env.component.libraries.first;
     Library secondLibrary = env.component.libraries.last;
-    if (firstLibrary.importUri.scheme == "dart" &&
+    if (firstLibrary.importUri.isScheme("dart") &&
         firstLibrary.importUri.path == "core") {
       _coreLibrary = firstLibrary;
       _testLibrary = secondLibrary;
     } else {
       assert(
-          secondLibrary.importUri.scheme == "dart" &&
+          secondLibrary.importUri.isScheme("dart") &&
               secondLibrary.importUri.path == "core",
           "One of the libraries is expected to be 'dart:core'.");
       _coreLibrary == secondLibrary;

pkg/front_end/test/fasta/type_inference/type_constraint_gatherer_test.dart

@@ -48,13 +48,13 @@ class TypeConstraintGathererTest {
         "the core library and the test library.");
     Library firstLibrary = env.component.libraries.first;
     Library secondLibrary = env.component.libraries.last;
-    if (firstLibrary.importUri.scheme == "dart" &&
+    if (firstLibrary.importUri.isScheme("dart") &&
         firstLibrary.importUri.path == "core") {
       _coreLibrary = firstLibrary;
       _testLibrary = secondLibrary;
     } else {
       assert(
-          secondLibrary.importUri.scheme == "dart" &&
+          secondLibrary.importUri.isScheme("dart") &&
               secondLibrary.importUri.path == "core",
           "One of the libraries is expected to be 'dart:core'.");
       _coreLibrary == secondLibrary;

pkg/front_end/test/fasta/type_inference/type_schema_environment_nnbd_test.dart

@@ -46,13 +46,13 @@ class TypeSchemaEnvironmentTest {
         "the core library and the test library.");
     Library firstLibrary = typeParserEnvironment.component.libraries.first;
     Library secondLibrary = typeParserEnvironment.component.libraries.last;
-    if (firstLibrary.importUri.scheme == "dart" &&
+    if (firstLibrary.importUri.isScheme("dart") &&
         firstLibrary.importUri.path == "core") {
       _coreLibrary = firstLibrary;
       _testLibrary = secondLibrary;
     } else {
       assert(
-          secondLibrary.importUri.scheme == "dart" &&
+          secondLibrary.importUri.isScheme("dart") &&
               secondLibrary.importUri.path == "core",
           "One of the libraries is expected to be 'dart:core'.");
       _coreLibrary == secondLibrary;

pkg/front_end/test/fasta/type_inference/type_schema_environment_test.dart

@@ -46,13 +46,13 @@ class TypeSchemaEnvironmentTest {
         "the core library and the test library.");
     Library firstLibrary = typeParserEnvironment.component.libraries.first;
     Library secondLibrary = typeParserEnvironment.component.libraries.last;
-    if (firstLibrary.importUri.scheme == "dart" &&
+    if (firstLibrary.importUri.isScheme("dart") &&
         firstLibrary.importUri.path == "core") {
       _coreLibrary = firstLibrary;
       _testLibrary = secondLibrary;
     } else {
       assert(
-          secondLibrary.importUri.scheme == "dart" &&
+          secondLibrary.importUri.isScheme("dart") &&
               secondLibrary.importUri.path == "core",
           "One of the libraries is expected to be 'dart:core'.");
       _coreLibrary == secondLibrary;

pkg/front_end/test/fasta/types/legacy_upper_bound_helper.dart

@@ -28,13 +28,13 @@ abstract class LegacyUpperBoundTest {
         "the core library and the test library.");
     Library firstLibrary = env.component.libraries.first;
     Library secondLibrary = env.component.libraries.last;
-    if (firstLibrary.importUri.scheme == "dart" &&
+    if (firstLibrary.importUri.isScheme("dart") &&
         firstLibrary.importUri.path == "core") {
       coreLibrary = firstLibrary;
       testLibrary = secondLibrary;
     } else {
       assert(
-          secondLibrary.importUri.scheme == "dart" &&
+          secondLibrary.importUri.isScheme("dart") &&
               secondLibrary.importUri.path == "core",
           "One of the libraries is expected to be 'dart:core'.");
       coreLibrary = secondLibrary;

pkg/front_end/test/hot_reload_e2e_test.dart

@@ -330,7 +330,7 @@ Future<Null> writeProgram(Component component, Uri outputUri) async {
   // TODO(sigmund): the incremental generator should always filter these
   // libraries instead.
   new BinaryPrinter(sink,
-          libraryFilter: (library) => library.importUri.scheme != 'dart')
+          libraryFilter: (library) => !library.importUri.isScheme('dart'))
       .writeComponentFile(component);
   await sink.close();
 }

pkg/front_end/test/incremental_dart2js_tester.dart

@@ -220,7 +220,7 @@ class Dart2jsTester {
     uris = c.uriToSource.values
         .map((s) => s.importUri)
         .whereType<Uri>()
-        .where((u) => u.scheme != "dart")
+        .where((u) => !u.isScheme("dart"))
         .toSet()
         .toList();
 

pkg/front_end/test/incremental_flutter_tester.dart

@@ -120,7 +120,7 @@ Future<void> main(List<String> args) async {
   List<Uri> uris = c.uriToSource.values
       .map((s) => s.importUri)
       .whereType<Uri>()
-      .where((u) => u.scheme != "dart")
+      .where((u) => !u.isScheme("dart"))
       .toSet()
       .toList();