Run smooth scroll animations on the compositor when possible

third_party/WebKit/Source/platform/scroll/ProgrammaticScrollAnimator.cpp

 // Copyright 2014 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.
 
 #include "config.h"
 #include "platform/scroll/ProgrammaticScrollAnimator.h"
 
 #include "platform/geometry/IntPoint.h"
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/scroll/ScrollableArea.h"
@@ skipping 47 matching lines @@
         WebScrollOffsetAnimationCurve::ScrollDurationDeltaBased));
 
     m_scrollableArea->registerForAnimation();
     if (!m_scrollableArea->scheduleAnimation()) {
         resetAnimationState();
         notifyPositionChanged(IntPoint(offset.x(), offset.y()));
     }
     m_runState = RunState::WaitingToSendToCompositor;
 }
 
+void ProgrammaticScrollAnimator::cancelAnimation()
+{
+    ASSERT(m_runState != RunState::RunningOnCompositorButNeedsUpdate);
+    ScrollAnimatorCompositorCoordinator::cancelAnimation();
+}
+
 void ProgrammaticScrollAnimator::tickAnimation(double monotonicTime)
 {
     if (m_runState != RunState::RunningOnMainThread)
         return;
 
     if (!m_startTime)
         m_startTime = monotonicTime;
     double elapsedTime = monotonicTime - m_startTime;
     bool isFinished = (elapsedTime > m_animationCurve->duration());
     FloatPoint offset = m_animationCurve->getValue(elapsedTime);
@@ skipping 70 matching lines @@
         m_scrollableArea->registerForAnimation();
         if (!m_scrollableArea->scheduleAnimation()) {
             resetAnimationState();
             notifyPositionChanged(IntPoint(m_targetOffset.x(), m_targetOffset.y()));
         }
     }
 }
 
 void ProgrammaticScrollAnimator::notifyCompositorAnimationFinished(int groupId)
 {
+    ASSERT(m_runState != RunState::RunningOnCompositorButNeedsUpdate);
     ScrollAnimatorCompositorCoordinator::compositorAnimationFinished(groupId);
 }
 
 DEFINE_TRACE(ProgrammaticScrollAnimator)
 {
     visitor->trace(m_scrollableArea);
     ScrollAnimatorCompositorCoordinator::trace(visitor);
 }
 
 } // namespace blink