Replace Scrollbar with Scrollbar2 (#8133)

examples/flutter_gallery/lib/demo/list_demo.dart

@@ -190,7 +190,7 @@ class ListDemoState extends State<ListDemo> {
           ),
         ],
       ),
-      body: new Scrollbar2(
+      body: new Scrollbar(
         child: new ListView(
           padding: new EdgeInsets.symmetric(vertical: _dense ? 4.0 : 8.0),
           children: listItems.toList(),

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

@@ -447,7 +447,7 @@ class _LicensePageState extends State<LicensePage> {
       ),
       body: new DefaultTextStyle(
         style: Theme.of(context).textTheme.caption,
-        child: new Scrollbar2(
+        child: new Scrollbar(
           child: new ListView(
             padding: const EdgeInsets.symmetric(horizontal: 8.0, vertical: 12.0),
             shrinkWrap: true,

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

@@ -184,7 +184,7 @@ class _DropdownMenuState<T> extends State<_DropdownMenu<T>> {
           textStyle: route.style,
           child: new ScrollConfiguration(
             delegate: new _DropdownScrollConfigurationDelegate(Theme.of(context).platform),
-            child: new Scrollbar2(
+            child: new Scrollbar(
               child: new ListView(
                 controller: config.route.scrollController,
                 padding: _kMenuVerticalPadding,

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

@@ -10,22 +10,22 @@ import 'package:flutter/widgets.dart';
 
 import 'theme.dart';
 
-class Scrollbar2 extends StatefulWidget {
-  Scrollbar2({
+class Scrollbar extends StatefulWidget {
+  Scrollbar({
     Key key,
     this.child,
   }) : super(key: key);
 
-  /// The subtree to place inside the [Scrollbar2]. This should include
+  /// The subtree to place inside the [Scrollbar]. This should include
   /// a source of [ScrollNotification2] notifications, typically a [Scrollable2]
   /// widget.
   final Widget child;
 
   @override
-  _Scrollbar2State createState() => new _Scrollbar2State();
+  _ScrollbarState createState() => new _ScrollbarState();
 }
 
-class _Scrollbar2State extends State<Scrollbar2> with TickerProviderStateMixin {
+class _ScrollbarState extends State<Scrollbar> with TickerProviderStateMixin {
   _ScrollbarController _controller;
 
   @override
@@ -179,193 +179,3 @@ class _ScrollbarPainter extends CustomPainter {
     return oldDelegate.controller != controller;
   }
 }
-
-////////////////////////////////////////////////////////////////////////////////
-// DELETE EVERYTHING BELOW THIS LINE WHEN REMOVING LEGACY SCROLLING CODE
-////////////////////////////////////////////////////////////////////////////////
-
-const double _kMinScrollbarThumbExtent = 18.0;
-const double _kScrollbarThumbGirth = 6.0;
-const Duration _kScrollbarThumbFadeDuration = const Duration(milliseconds: 300);
-
-class _Painter extends CustomPainter {
-  _Painter({
-    this.scrollOffset,
-    this.scrollDirection,
-    this.contentExtent,
-    this.containerExtent,
-    this.color
-  });
-
-  final double scrollOffset;
-  final Axis scrollDirection;
-  final double contentExtent;
-  final double containerExtent;
-  final Color color;
-
-  void paintScrollbar(Canvas canvas, Size size) {
-    Point thumbOrigin;
-    Size thumbSize;
-
-    switch (scrollDirection) {
-      case Axis.vertical:
-        double thumbHeight = size.height * containerExtent / contentExtent;
-        thumbHeight = thumbHeight.clamp(_kMinScrollbarThumbExtent, size.height);
-        final double maxThumbTop = size.height - thumbHeight;
-        double thumbTop = (scrollOffset / (contentExtent - containerExtent)) * maxThumbTop;
-        thumbTop = thumbTop.clamp(0.0, maxThumbTop);
-        thumbOrigin = new Point(size.width - _kScrollbarThumbGirth, thumbTop);
-        thumbSize = new Size(_kScrollbarThumbGirth, thumbHeight);
-        break;
-      case Axis.horizontal:
-        double thumbWidth = size.width * containerExtent / contentExtent;
-        thumbWidth = thumbWidth.clamp(_kMinScrollbarThumbExtent, size.width);
-        final double maxThumbLeft = size.width - thumbWidth;
-        double thumbLeft = (scrollOffset / (contentExtent - containerExtent)) * maxThumbLeft;
-        thumbLeft = thumbLeft.clamp(0.0, maxThumbLeft);
-        thumbOrigin = new Point(thumbLeft, size.height - _kScrollbarThumbGirth);
-        thumbSize = new Size(thumbWidth, _kScrollbarThumbGirth);
-        break;
-    }
-
-    final Paint paint = new Paint()..color = color;
-    canvas.drawRect(thumbOrigin & thumbSize, paint);
-  }
-
-  @override
-  void paint(Canvas canvas, Size size) {
-    if (scrollOffset == null || color.alpha == 0)
-      return;
-    paintScrollbar(canvas, size);
-  }
-
-  @override
-  bool shouldRepaint(_Painter oldPainter) {
-    return oldPainter.scrollOffset != scrollOffset
-        || oldPainter.scrollDirection != scrollDirection
-        || oldPainter.contentExtent != contentExtent
-        || oldPainter.containerExtent != containerExtent
-        || oldPainter.color != color;
-  }
-}
-
-/// Displays a scrollbar that tracks the scrollOffset of its child's [Scrollable]
-/// descendant. If the Scrollbar's child has more than one Scrollable descendant
-/// the scrollableKey parameter can be used to identify the one the Scrollbar
-/// should track.
-class Scrollbar extends StatefulWidget {
-  /// Creates a scrollbar.
-  ///
-  /// The child argument must not be null.
-  Scrollbar({ Key key, this.scrollableKey, this.child }) : super(key: key) {
-    assert(child != null);
-  }
-
-  /// Identifies the [Scrollable] descendant of child that the scrollbar will
-  /// track. Can be null if there's only one [Scrollable] descendant.
-  final Key scrollableKey;
-
-  /// The scrollbar will be stacked on top of this child. The scrollbar will
-  /// display when child's [Scrollable] descendant is scrolled.
-  final Widget child;
-
-  @override
-  _ScrollbarState createState() => new _ScrollbarState();
-}
-
-class _ScrollbarState extends State<Scrollbar> with SingleTickerProviderStateMixin {
-  AnimationController _fade;
-  CurvedAnimation _opacity;
-  double _scrollOffset;
-  Axis _scrollDirection;
-  double _containerExtent;
-  double _contentExtent;
-
-  @override
-  void initState() {
-    super.initState();
-    _fade = new AnimationController(duration: _kScrollbarThumbFadeDuration, vsync: this);
-    _opacity = new CurvedAnimation(parent: _fade, curve: Curves.fastOutSlowIn);
-  }
-
-  @override
-  void dispose() {
-    _fade.stop();
-    super.dispose();
-  }
-
-  void _updateState(ScrollableState scrollable) {
-    if (scrollable.scrollBehavior is! ExtentScrollBehavior)
-      return;
-    if (_scrollOffset != scrollable.scrollOffset)
-      setState(() { _scrollOffset = scrollable.scrollOffset; });
-    if (_scrollDirection != scrollable.config.scrollDirection)
-      setState(() { _scrollDirection = scrollable.config.scrollDirection; });
-    final ExtentScrollBehavior scrollBehavior = scrollable.scrollBehavior;
-    if (_contentExtent != scrollBehavior.contentExtent)
-      setState(() { _contentExtent = scrollBehavior.contentExtent; });
-    if (_containerExtent != scrollBehavior.containerExtent)
-      setState(() { _containerExtent = scrollBehavior.containerExtent; });
-  }
-
-  void _onScrollStarted(ScrollableState scrollable) {
-    _updateState(scrollable);
-  }
-
-  void _onScrollUpdated(ScrollableState scrollable) {
-    _updateState(scrollable);
-    if (_fade.status != AnimationStatus.completed)
-      _fade.forward();
-  }
-
-  void _onScrollEnded(ScrollableState scrollable) {
-    _updateState(scrollable);
-    _fade.reverse();
-  }
-
-  bool _handleScrollNotification(ScrollNotification notification) {
-    if (config.scrollableKey == null) {
-      if (notification.depth != 0)
-        return false;
-    } else if (config.scrollableKey != notification.scrollable.config.key) {
-      return false;
-    }
-
-    final ScrollableState scrollable = notification.scrollable;
-    switch(notification.kind) {
-      case ScrollNotificationKind.started:
-        _onScrollStarted(scrollable);
-        break;
-      case ScrollNotificationKind.updated:
-        _onScrollUpdated(scrollable);
-        break;
-      case ScrollNotificationKind.ended:
-        _onScrollEnded(scrollable);
-        break;
-    }
-    return false;
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    return new NotificationListener<ScrollNotification>(
-      onNotification: _handleScrollNotification,
-      child: new AnimatedBuilder(
-        animation: _opacity,
-        builder: (BuildContext context, Widget child) {
-          return new CustomPaint(
-            foregroundPainter: new _Painter(
-              scrollOffset: _scrollOffset,
-              scrollDirection: _scrollDirection,
-              containerExtent: _containerExtent,
-              contentExtent: _contentExtent,
-              color: Theme.of(context).highlightColor.withOpacity(_opacity.value)
-            ),
-            child: child
-          );
-        },
-        child: config.child
-      )
-    );
-  }
-}

packages/flutter/test/material/scrollbar_paint_test.dart

@@ -9,13 +9,13 @@ import '../rendering/mock_canvas.dart';
 
 void main() {
   testWidgets('Viewport2 basic test', (WidgetTester tester) async {
-    await tester.pumpWidget(new Scrollbar2(
+    await tester.pumpWidget(new Scrollbar(
       child: new SingleChildScrollView(
         child: const SizedBox(width: 4000.0, height: 4000.0),
       ),
     ));
-    expect(find.byType(Scrollbar2), isNot(paints..rect()));
+    expect(find.byType(Scrollbar), isNot(paints..rect()));
     await tester.fling(find.byType(SingleChildScrollView), const Offset(0.0, -10.0), 10.0);
-    expect(find.byType(Scrollbar2), paints..rect());
+    expect(find.byType(Scrollbar), paints..rect());
   });
 }

packages/flutter/test/material/scrollbar_test.dart

@@ -16,7 +16,7 @@ void main() {
           ),
           height: 200.0,
           width: 300.0,
-          child: new Scrollbar2(
+          child: new Scrollbar(
             child: new ListView(
               children: <Widget>[
                 new Container(height: 40.0, child: new Text('0')),

packages/flutter/test/widgets/slivers_evil_test.dart

@@ -74,7 +74,7 @@ void main() {
     await tester.pumpWidget(
       new ScrollConfiguration2(
         behavior: new TestBehavior(),
-        child: new Scrollbar2(
+        child: new Scrollbar(
           child: new Scrollable2(
             axisDirection: AxisDirection.down,
             physics: const TestScrollPhysics(),