Add metadata annotations to library definitions.

BUG=
R=ahe@google.com

Review-Url: https://codereview.chromium.org/2893803003 .

pkg/kernel/binary.md

@@ -166,6 +166,7 @@ type Library {
   StringReference name;
   // An absolute path URI to the .dart file from which the library was created.
   UriReference fileUri;
+  List<Expression> annotations;
   List<LibraryDependency> libraryDependencies;
   List<Class> classes;
   List<Field> fields;

pkg/kernel/lib/ast.dart

@@ -264,6 +264,7 @@ class Library extends NamedNode implements Comparable<Library> {
   bool isExternal;
 
   String name;
+  final List<Expression> annotations;
   final List<LibraryDependency> dependencies;
   final List<Typedef> typedefs;
   final List<Class> classes;
@@ -273,6 +274,7 @@ class Library extends NamedNode implements Comparable<Library> {
   Library(this.importUri,
       {this.name,
       this.isExternal: false,
+      List<Expression> annotations,
       List<LibraryDependency> dependencies,
       List<Typedef> typedefs,
       List<Class> classes,
@@ -280,7 +282,8 @@ class Library extends NamedNode implements Comparable<Library> {
       List<Field> fields,
       this.fileUri,
       Reference reference})
-      : this.dependencies = dependencies ?? <LibraryDependency>[],
+      : this.annotations = annotations ?? <Expression>[],
+        this.dependencies = dependencies ?? <LibraryDependency>[],
         this.typedefs = typedefs ?? <Typedef>[],
         this.classes = classes ?? <Class>[],
         this.procedures = procedures ?? <Procedure>[],
@@ -321,6 +324,11 @@ class Library extends NamedNode implements Comparable<Library> {
     typedefs.add(typedef_);
   }
 
+  void addAnnotation(Expression node) {
+    node.parent = this;
+    annotations.add(node);
+  }
+
   void computeCanonicalNames() {
     assert(canonicalName != null);
     for (var typedef_ in typedefs) {

pkg/kernel/lib/binary/ast_from_binary.dart

@@ -354,10 +354,10 @@ class BinaryBuilder {
       library.fileUri = fileUri;
     }
 
-    _readLibraryDependencies(library);
-
     debugPath.add(library.name ?? library.importUri?.toString() ?? 'library');
 
+    _fillTreeNodeList(library.annotations, readExpression, library);
+    _readLibraryDependencies(library);
     _mergeNamedNodeList(library.typedefs, readTypedef, library);
     _mergeNamedNodeList(library.classes, readClass, library);
     _mergeNamedNodeList(library.fields, readField, library);

pkg/kernel/lib/binary/ast_to_binary.dart

@@ -255,6 +255,7 @@ class BinaryPrinter extends Visitor {
     writeStringReference(node.name ?? '');
     // TODO(jensj): We save (almost) the same URI twice.
     writeUriReference(node.fileUri ?? '');
+    writeAnnotationList(node.annotations);
     writeLibraryDependencies(node);
     writeNodeList(node.typedefs);
     writeNodeList(node.classes);

pkg/kernel/lib/text/ast_to_text.dart

@@ -265,6 +265,7 @@ class Printer extends Visitor<Null> {
   }
 
   void writeLibraryFile(Library library) {
+    writeAnnotationList(library.annotations);
     writeWord('library');
     if (library.name != null) {
       writeWord(library.name);
@@ -308,6 +309,7 @@ class Printer extends Visitor<Null> {
         }
         writeWord('external');
       }
+      writeAnnotationList(library.annotations);
       writeWord('library');
       if (library.name != null) {
         writeWord(library.name);

runtime/vm/kernel.cc

@@ -53,6 +53,7 @@ void Library::AcceptTreeVisitor(TreeVisitor* visitor) {
 
 
 void Library::VisitChildren(Visitor* visitor) {
+  VisitList(&typedefs(), visitor);
   VisitList(&classes(), visitor);
   VisitList(&procedures(), visitor);
   VisitList(&fields(), visitor);

runtime/vm/kernel.h

@@ -474,6 +474,7 @@ class Library : public LinkedNode {
   StringIndex import_uri() { return import_uri_index_; }
   intptr_t source_uri_index() { return source_uri_index_; }
   StringIndex name() { return name_index_; }
+  List<Expression>& annotations() { return annotations_; }
   List<LibraryDependency>& dependencies() { return dependency_; }
   List<Typedef>& typedefs() { return typedefs_; }
   List<Class>& classes() { return classes_; }
@@ -492,6 +493,7 @@ class Library : public LinkedNode {
   StringIndex name_index_;
   StringIndex import_uri_index_;
   intptr_t source_uri_index_;
+  List<Expression> annotations_;
   List<LibraryDependency> dependency_;
   List<Typedef> typedefs_;
   List<Class> classes_;

runtime/vm/kernel_binary.cc

@@ -182,6 +182,7 @@ Library* Library::ReadFrom(Reader* reader) {
   source_uri_index_ = reader->ReadUInt();
   reader->set_current_script_id(source_uri_index_);
 
+  annotations_.ReadFromStatic<Expression>(reader);
   dependencies().ReadFromStatic<LibraryDependency>(reader);
   int num_typedefs = reader->ReadUInt();
   typedefs().EnsureInitialized(num_typedefs);