Replace EdgeInsets.TRBL with EdgeInsets.fromLTRB

This matches the pattern from Rect. I've left EdgeInsets.TRBL marked as
deprecated to give clients a chance to update.

Fixes #2860

examples/material_gallery/lib/demo/tabs_fab_demo.dart

@@ -78,7 +78,7 @@ class _TabsFabDemoState extends State<TabsFabDemo> {
 
         return new Container(
           key: new ValueKey<String>(page.label),
-          padding: const EdgeInsets.TRBL(48.0, 48.0, 96.0, 48.0),
+          padding: const EdgeInsets.fromLTRB(48.0, 48.0, 48.0, 96.0),
           child: new Card(
             child: new Center(
               child: new Text(page.label, style: textStyle)

examples/stocks/lib/stock_row.dart

@@ -72,7 +72,7 @@ class StockRow extends StatelessWidget {
       onDoubleTap: _getHandler(onDoubleTap),
       onLongPress: _getHandler(onLongPressed),
       child: new Container(
-        padding: const EdgeInsets.TRBL(16.0, 16.0, 20.0, 16.0),
+        padding: const EdgeInsets.fromLTRB(16.0, 16.0, 16.0, 20.0),
         decoration: new BoxDecoration(
           border: new Border(
             bottom: new BorderSide(color: Theme.of(context).dividerColor)

packages/flutter/lib/src/material/constants.dart

@@ -33,7 +33,7 @@ const double kFadingEdgeLength = 12.0;
 const double kPressedStateDuration = 64.0; // units?
 const Duration kThemeChangeDuration = const Duration(milliseconds: 200);
 
-const EdgeInsets kDialogHeadingPadding = const EdgeInsets.TRBL(24.0, 24.0, 20.0, 24.0);
+const EdgeInsets kDialogHeadingPadding = const EdgeInsets.fromLTRB(24.0, 24.0, 24.0, 20.0);
 
 const double kRadialReactionRadius = 24.0; // Pixels
 const Duration kRadialReactionDuration = const Duration(milliseconds: 200);

packages/flutter/lib/src/material/dialog.dart

@@ -62,7 +62,7 @@ class Dialog extends StatelessWidget {
     if (title != null) {
       EdgeInsets padding = titlePadding;
       if (padding == null)
-        padding = new EdgeInsets.TRBL(24.0, 24.0, content == null ? 20.0 : 0.0, 24.0);
+        padding = new EdgeInsets.fromLTRB(24.0, 24.0, 24.0, content == null ? 20.0 : 0.0);
       dialogBody.add(new Padding(
         padding: padding,
         child: new DefaultTextStyle(
@@ -75,7 +75,7 @@ class Dialog extends StatelessWidget {
     if (content != null) {
       EdgeInsets padding = contentPadding;
       if (padding == null)
-        padding = const EdgeInsets.TRBL(20.0, 24.0, 24.0, 24.0);
+        padding = const EdgeInsets.fromLTRB(24.0, 20.0, 24.0, 24.0);
       dialogBody.add(new Padding(
         padding: padding,
         child: new DefaultTextStyle(

packages/flutter/lib/src/painting/box_painter.dart

@@ -112,7 +112,7 @@ class Border {
 
   /// The widths of the sides of this border represented as an EdgeInsets.
   EdgeInsets get dimensions {
-    return new EdgeInsets.TRBL(top.width, right.width, bottom.width, left.width);
+    return new EdgeInsets.fromLTRB(left.width, top.width, right.width, bottom.width);
   }
 
   /// Whether all four sides of the border are identical.

packages/flutter/lib/src/painting/edge_insets.dart

@@ -12,8 +12,15 @@ import 'basic_types.dart';
 /// example, the padding inside a box can be represented using this class.
 class EdgeInsets {
   /// Constructs insets from offsets from the top, right, bottom and left.
+  ///
+  /// We'll be removing this function sometime soon. Please use
+  /// [EdgeInsets.fromLTRB] instead.
+  @Deprecated('soon. Use fromLTRB instead.')
   const EdgeInsets.TRBL(this.top, this.right, this.bottom, this.left);
 
+  /// Constructs insets from offsets from the left, top, right, and bottom.
+  const EdgeInsets.fromLTRB(this.left, this.top, this.right, this.bottom);
+
   /// Constructs insets where all the offsets are value.
   const EdgeInsets.all(double value)
       : top = value, right = value, bottom = value, left = value;
@@ -56,63 +63,63 @@ class EdgeInsets {
   Size get collapsedSize => new Size(horizontal, vertical);
 
   /// An EdgeInsets with top and bottom as well as left and right flipped.
-  EdgeInsets get flipped => new EdgeInsets.TRBL(bottom, left, top, right);
+  EdgeInsets get flipped => new EdgeInsets.fromLTRB(left, top, right, bottom);
 
   Rect inflateRect(Rect rect) {
     return new Rect.fromLTRB(rect.left - left, rect.top - top, rect.right + right, rect.bottom + bottom);
   }
 
   EdgeInsets operator -(EdgeInsets other) {
-    return new EdgeInsets.TRBL(
+    return new EdgeInsets.fromLTRB(
+      left - other.left,
       top - other.top,
       right - other.right,
-      bottom - other.bottom,
-      left - other.left
+      bottom - other.bottom
     );
   }
 
   EdgeInsets operator +(EdgeInsets other) {
-    return new EdgeInsets.TRBL(
+    return new EdgeInsets.fromLTRB(
+      left + other.left,
       top + other.top,
       right + other.right,
-      bottom + other.bottom,
-      left + other.left
+      bottom + other.bottom
     );
   }
 
   EdgeInsets operator *(double other) {
-    return new EdgeInsets.TRBL(
+    return new EdgeInsets.fromLTRB(
+      left * other,
       top * other,
       right * other,
-      bottom * other,
-      left * other
+      bottom * other
     );
   }
 
   EdgeInsets operator /(double other) {
-    return new EdgeInsets.TRBL(
+    return new EdgeInsets.fromLTRB(
+      left / other,
       top / other,
       right / other,
-      bottom / other,
-      left / other
+      bottom / other
     );
   }
 
   EdgeInsets operator ~/(double other) {
-    return new EdgeInsets.TRBL(
+    return new EdgeInsets.fromLTRB(
+      (left ~/ other).toDouble(),
       (top ~/ other).toDouble(),
       (right ~/ other).toDouble(),
-      (bottom ~/ other).toDouble(),
-      (left ~/ other).toDouble()
+      (bottom ~/ other).toDouble()
     );
   }
 
   EdgeInsets operator %(double other) {
-    return new EdgeInsets.TRBL(
+    return new EdgeInsets.fromLTRB(
+      left % other,
       top % other,
       right % other,
-      bottom % other,
-      left % other
+      bottom % other
     );
   }
 
@@ -126,16 +133,16 @@ class EdgeInsets {
       return b * t;
     if (b == null)
       return a * (1.0 - t);
-    return new EdgeInsets.TRBL(
+    return new EdgeInsets.fromLTRB(
+      ui.lerpDouble(a.left, b.left, t),
       ui.lerpDouble(a.top, b.top, t),
       ui.lerpDouble(a.right, b.right, t),
-      ui.lerpDouble(a.bottom, b.bottom, t),
-      ui.lerpDouble(a.left, b.left, t)
+      ui.lerpDouble(a.bottom, b.bottom, t)
     );
   }
 
   /// An EdgeInsets with zero offsets in each direction.
-  static const EdgeInsets zero = const EdgeInsets.TRBL(0.0, 0.0, 0.0, 0.0);
+  static const EdgeInsets zero = const EdgeInsets.all(0.0);
 
   @override
   bool operator ==(dynamic other) {

packages/flutter/lib/src/widgets/app.dart

@@ -105,7 +105,7 @@ class WidgetsApp extends StatefulWidget {
 }
 
 EdgeInsets _getPadding(ui.WindowPadding padding) {
-  return new EdgeInsets.TRBL(padding.top, padding.right, padding.bottom, padding.left);
+  return new EdgeInsets.fromLTRB(padding.left, padding.top, padding.right, padding.bottom);
 }
 
 class WidgetsAppState<T extends WidgetsApp> extends State<T> implements BindingObserver {

packages/flutter/test/widget/scrollable_list_hit_testing_test.dart

@@ -100,7 +100,7 @@ void main() {
         new ScrollableList(
           key: new GlobalKey(),
           itemExtent: 290.0,
-          padding: new EdgeInsets.TRBL(20.0, 15.0, 10.0, 5.0),
+          padding: new EdgeInsets.fromLTRB(5.0, 20.0, 15.0, 10.0),
           children: items.map((int item) {
             return new Container(
               child: new GestureDetector(
@@ -135,7 +135,7 @@ void main() {
           key: new GlobalKey(),
           itemExtent: 290.0,
           scrollAnchor: ViewportAnchor.end,
-          padding: new EdgeInsets.TRBL(20.0, 15.0, 10.0, 5.0),
+          padding: new EdgeInsets.fromLTRB(5.0, 20.0, 15.0, 10.0),
           children: items.map((int item) {
             return new Container(
               child: new GestureDetector(