Add zone task support for request-anim.

sdk/lib/html/dart2js/html_dart2js.dart

Index: sdk/lib/html/dart2js/html_dart2js.dart
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index 492a1d929fa6b8c409de5be4e38d2e2d0c4d0ce1..f3d743e65774a1056b63cbef2b3602676173f685 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -34485,6 +34485,77 @@ class WheelEvent extends MouseEvent {
 // BSD-style license that can be found in the LICENSE file.
 
 
+typedef void RemoveFrameRequestMapping(int id);
+
+/**
+ * The task object representing animation-frame requests.
+ *
+ * For historical reasons, [Window.requestAnimationFrame] returns an integer
+ * to users. However, zone-tasks must be unique objects, and an integer thus
+ * doesn't work. The [Window] class thus keeps a mapping from the id to the
+ * corresponding task object. All zone related operations work on this task
+ * object, whereas users of [Window.requestAnimationFrame] only see the integer
+ * id.
+ *
+ * Since this mapping takes space, it must be removed as soon as the animation-
+ * frame task triggered. The default-implementations do this automatically, but
+ * intercepted implementations of `requestAnimationFrame` must ensure to
+ * call the [AnimationFrameRequestSpecification.removeMapping] function that is
+ * provided in the task specification.
+ */
+abstract class AnimationFrameTask {
+  /** The id that is returned to users. */
+  int get id;
+
+  /** The function that is invoked when the user cancels the request. */
+  void cancel(Window window);
+
+  /** The zone in which the task should run (and cancel). */
+  Zone get zone;
+}
+
+class _AnimationFrameTask implements AnimationFrameTask {
+  final int id;
+  final Zone zone;
+  final FrameRequestCallback _callback;
+
+  _AnimationFrameTask(this.id, this.zone, this._callback);
+
+  void cancel(Window window) {
+    window._cancelAnimationFrame(this.id);
+  }
+}
+
+/**
+ * The task specification for an animation-frame request.
+ *
+ * The task specification of animation-frame requests include a `removeMapping`
+ * function. This function must be called by the created task before it
+ * runs the frame-request callback.
+ */
+class AnimationFrameRequestSpecification implements TaskSpecification {
+  final Window window;
+  /**
+   * The callback that should be executed when the animation-frame is ready.
+   *
+   * Note that the callback hasn't been registered in any zone yet.
+   */
+  final FrameRequestCallback callback;
+
+  /**
+   * The function that should be invoked by the task before running [callback].
+   *
+   * See [AnimationFrame].
+   */
+  final RemoveFrameRequestMapping removeMapping;
+
+  AnimationFrameRequestSpecification(
+      this.window, this.callback, this.removeMapping);
+
+  String get name => "dart.html.request-animation-frame";
+  bool get isOneShot => true;
+}
+
 @DocsEditable()
 /**
  * Top-level container for the current browser tab or window.
@@ -34540,9 +34611,7 @@ class Window extends EventTarget implements WindowEventHandlers, WindowBase, Glo
    */
   Future<num> get animationFrame {
     var completer = new Completer<num>.sync();
-    requestAnimationFrame((time) {
-      completer.complete(time);
-    });
+    requestAnimationFrame(completer.complete);
     return completer.future;
   }
 
@@ -34607,6 +34676,12 @@ class Window extends EventTarget implements WindowEventHandlers, WindowBase, Glo
   }
 
   /**
+   * Maps animation-frame request ids to their task objects.
+   */
+  static final Map<int, _AnimationFrameTask> _animationFrameTasks =
+      <int, _AnimationFrameTask>{};
+
+  /**
    * Called to draw an animation frame and then request the window to repaint
    * after [callback] has finished (creating the animation).
    *
@@ -34625,7 +34700,35 @@ class Window extends EventTarget implements WindowEventHandlers, WindowBase, Glo
   @DomName('Window.requestAnimationFrame')
   int requestAnimationFrame(FrameRequestCallback callback) {
     _ensureRequestAnimationFrame();
-    return _requestAnimationFrame(_wrapZone/*<dynamic, num>*/(callback));
+    if (identical(Zone.current, Zone.ROOT)) {
+      return _requestAnimationFrame(callback);
+    }
+    var spec = new AnimationFrameRequestSpecification(
+        this, callback, _removeTaskMapping);
+    var task = Zone.current.createTask/*<AnimationFrameTask>*/(
+        _createAnimationFrameTask, spec);
+    _animationFrameTasks[task.id] = task;
+    return task.id;
+  }
+
+  static _AnimationFrameTask _createAnimationFrameTask(
+      AnimationFrameRequestSpecification spec, Zone zone) {
+    var task;
+    var id = spec.window._requestAnimationFrame((num time) {
+      spec.removeMapping(task.id);
+      zone.runTask(_runAnimationFrame, task, time);
+    });
+    var callback = zone.registerUnaryCallback(spec.callback);
+    task = new _AnimationFrameTask(id, zone, callback);
+    return task;
+  }
+
+  static void _removeTaskMapping(int id) {
+    _animationFrameTasks.remove(id);
+  }
+
+  static void _runAnimationFrame(_AnimationFrameTask task, num time) {
+    task._callback(time);
   }
 
   /**
@@ -34638,7 +34741,12 @@ class Window extends EventTarget implements WindowEventHandlers, WindowBase, Glo
    */
   void cancelAnimationFrame(int id) {
     _ensureRequestAnimationFrame();
-    _cancelAnimationFrame(id);
+    var task = _animationFrameTasks[id];
+    if (task == null) {
+      _cancelAnimationFrame(id);
+    }
+    _animationFrameTasks.remove(id);
+    task.cancel(this);
   }
 
   @JSName('requestAnimationFrame')