Takeover MT initiated animations from the compositor

third_party/WebKit/Source/platform/scroll/ScrollAnimatorCompositorCoordinator.h

 // 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.
 
 #ifndef ScrollAnimatorCompositorCoordinator_h
 #define ScrollAnimatorCompositorCoordinator_h
 
 #include "base/gtest_prod_util.h"
 #include "cc/animation/animation_curve.h"
 #include "platform/PlatformExport.h"
@@ skipping 18 matching lines @@
 public:
     virtual ~ScrollAnimatorCompositorCoordinator();
 
     bool hasAnimationThatRequiresService() const;
     void dispose();
 
     virtual bool hasRunningAnimation() const { return false; }
 
     virtual void resetAnimationState();
     virtual void cancelAnimation();
+    // Aborts the currently running scroll offset animation on the compositor
+    // and continues it on the main thread. This should only be called when in
+    // DocumentLifecycle::LifecycleState::CompositingClean state.
+    virtual void takeoverCompositorAnimation();
 
     virtual ScrollableArea* scrollableArea() const = 0;
     virtual void tickAnimation(double monotonicTime) = 0;
     virtual void updateCompositorAnimations() = 0;
     virtual void notifyCompositorAnimationFinished(int groupId) = 0;
     virtual void notifyCompositorAnimationAborted(int groupId) = 0;
     virtual void layerForCompositedScrollingDidChange(CompositorAnimationTimeline*) = 0;
 
     DEFINE_INLINE_VIRTUAL_TRACE() { }
 
 protected:
     explicit ScrollAnimatorCompositorCoordinator();
 
     bool addAnimation(PassOwnPtr<CompositorAnimation>);
     void removeAnimation();
-    void abortAnimation();
+    virtual void abortAnimation();
 
     void compositorAnimationFinished(int groupId);
     // Returns true if the compositor player was attached to a new layer.
     bool reattachCompositorPlayerIfNeeded(CompositorAnimationTimeline*);
 
     // WebCompositorAnimationDelegate implementation.
     void notifyAnimationStarted(double monotonicTime, int group) override;
     void notifyAnimationFinished(double monotonicTime, int group) override;
     void notifyAnimationAborted(double monotonicTime, int group) override;
     void notifyAnimationTakeover(
         double monotonicTime,
         double animationStartTime,
         scoped_ptr<cc::AnimationCurve>) override { };
 
     // CompositorAnimationPlayerClient implementation.
     CompositorAnimationPlayer* compositorPlayer() const override;
 
     friend class Internals;
     FRIEND_TEST_ALL_PREFIXES(ScrollAnimatorTest, MainThreadStates);
+    FRIEND_TEST_ALL_PREFIXES(ScrollAnimatorTest, AnimatedScrollTakeover);
 
     enum class RunState {
         // No animation.
         Idle,
 
         // Waiting to send an animation to the compositor. There might also
         // already be another animation running on the compositor that will need
         // to be canceled first.
         WaitingToSendToCompositor,
 
         // Running an animation on the compositor.
         RunningOnCompositor,
 
         // Running an animation on the compositor but needs update.
         RunningOnCompositorButNeedsUpdate,
 
         // Running an animation on the main thread.
         RunningOnMainThread,
 
         // Waiting to cancel the animation currently running on the compositor.
         // There is no pending animation to replace the canceled animation.
         WaitingToCancelOnCompositor,
 
         // Finished an animation that was running on the main thread or the
         // compositor thread. When in this state, post animation cleanup can
         // be performed.
-        PostAnimationCleanup
+        PostAnimationCleanup,
+
+        // Running an animation on the compositor but need to continue it
+        // on the main thread. This could happen if a main thread scrolling
+        // reason is added while animating the scroll offset.
+        RunningOnCompositorButNeedsTakeover,
     };
 
     OwnPtr<CompositorAnimationPlayer> m_compositorPlayer;
     int m_compositorAnimationAttachedToLayerId;
     RunState m_runState;
     int m_compositorAnimationId;
     int m_compositorAnimationGroupId;
 };
 
 } // namespace blink
 
 #endif // ScrollAnimatorCompositorCoordinator_h