Remove outdated radial_reaction.dart

We now draw radial reactions using Material.

packages/flutter/lib/material.dart

@@ -39,7 +39,6 @@ export 'src/material/page.dart';
 export 'src/material/popup_menu.dart';
 export 'src/material/popup_menu_item.dart';
 export 'src/material/progress_indicator.dart';
-export 'src/material/radial_reaction.dart';
 export 'src/material/radio.dart';
 export 'src/material/raised_button.dart';
 export 'src/material/scaffold.dart';

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

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-import 'dart:async';
-
-import 'package:flutter/animation.dart';
-import 'package:flutter/painting.dart';
-
-const Duration _kShowDuration = const Duration(milliseconds: 300);
-const Duration _kHideDuration = const Duration(milliseconds: 200);
-const Color _kOuterColor = const Color(0xFFFFFFFF);
-const Color _kInnerColor = const Color(0xFFFFFFFF);
-const double _kMaxOpacity = 0.2;
-
-int _roundOpacity(double opacity) {
-  return (255 * opacity).round();
-}
-
-/// A material design radial ink reaction
-///
-/// See [https://www.google.com/design/spec/animation/responsive-interaction.html#responsive-interaction-radial-action]
-class RadialReaction {
-  RadialReaction({
-    this.center,
-    this.radius,
-    Point startPosition
-  }) {
-    _outerOpacity = new AnimatedValue<double>(0.0, end: _kMaxOpacity, curve: Curves.easeOut);
-    _innerCenter = new AnimatedValue<Point>(startPosition, end: center, curve: Curves.easeOut);
-    _innerRadius = new AnimatedValue<double>(0.0, end: radius, curve: Curves.easeOut);
-    _showPerformance = new Performance(duration: _kShowDuration)
-      ..addListener(() {
-        _showPerformance.updateVariable(_outerOpacity);
-        _showPerformance.updateVariable(_innerCenter);
-        _showPerformance.updateVariable(_innerRadius);
-      });
-    _fade = new ValuePerformance<double>(
-      variable: new AnimatedValue<double>(1.0, end: 0.0, curve: Curves.easeIn),
-      duration: _kHideDuration
-    );
-  }
-
-  /// The center of the circle in which the reaction occurs
-  final Point center;
-
-  /// The radius of the circle in which the reaction occurs
-  final double radius;
-
-  Performance _showPerformance;
-  AnimatedValue<double> _outerOpacity;
-  AnimatedValue<Point> _innerCenter;
-  AnimatedValue<double> _innerRadius;
-
-  Future _showComplete;
-
-  ValuePerformance<double> _fade;
-
-  /// Show the reaction
-  ///
-  /// Returns a future that resolves when the reaction is completely revealed.
-  Future show() {
-    return _showComplete = _showPerformance.forward();
-  }
-
-  /// Hide the reaction
-  ///
-  /// Returns a future that resolves when the reaction is completely hidden.
-  Future hide() async {
-    await _showComplete;
-    await _fade.forward();
-  }
-
-  /// Call listener whenever the visual appearance of the reaction changes
-  void addListener(Function listener) {
-    _showPerformance.addListener(listener);
-    _fade.addListener(listener);
-  }
-
-  final Paint _outerPaint = new Paint();
-  final Paint _innerPaint = new Paint();
-
-  /// Paint the reaction onto the given canvas at the given offset
-  void paint(Canvas canvas, Offset offset) {
-    _outerPaint.color = _kOuterColor.withAlpha(_roundOpacity(_outerOpacity.value * _fade.value));
-    canvas.drawCircle(center + offset, radius, _outerPaint);
-
-    _innerPaint.color = _kInnerColor.withAlpha(_roundOpacity(_kMaxOpacity  * _fade.value));
-    canvas.drawCircle(_innerCenter.value + offset, _innerRadius.value, _innerPaint);
-  }
-}