Query compositing state only from UpdateAnimationState

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

 /*
  * Copyright (c) 2011, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 169 matching lines @@
             m_runState = RunState::RunningOnCompositorButNeedsUpdate;
         return true;
     }
 
     if ((targetPos - currentPosition()).isZero())
         return false;
 
     m_targetOffset = targetPos;
     m_startTime = m_timeFunction();
 
-    if (registerAndScheduleAnimation()) {
-        if (m_scrollableArea->shouldScrollOnMainThread()) {
-            createAnimationCurve();
-            m_runState = RunState::RunningOnMainThread;
-        } else {
-            m_runState = RunState::WaitingToSendToCompositor;
-        }
-    }
+    if (registerAndScheduleAnimation())
+        m_runState = RunState::WaitingToSendToCompositor;
 
     return true;
 }
 
 void ScrollAnimator::adjustAnimationAndSetScrollPosition(
     const DoublePoint& position, ScrollType scrollType)
 {
     DoublePoint adjustedPos = m_scrollableArea->clampScrollPosition(position);
     IntSize actualAdjustment = roundedIntPoint(adjustedPos) -
         roundedIntPoint(m_scrollableArea->scrollPositionDouble());
@@ skipping 89 matching lines @@
         compositorOffsetFromBlinkOffset(m_targetOffset),
         m_lastGranularity == ScrollByPixel ?
             CompositorScrollOffsetAnimationCurve::ScrollDurationInverseDelta :
             CompositorScrollOffsetAnimationCurve::ScrollDurationConstant);
     m_animationCurve->setInitialValue(compositorOffsetFromBlinkOffset(currentPosition()));
 }
 
 void ScrollAnimator::updateCompositorAnimations()
 {
     ScrollAnimatorCompositorCoordinator::updateCompositorAnimations();
-    if (m_runState == RunState::RunningOnMainThread) {
-        // We add a temporary main thread scrolling reason so that subsequent
-        // scrolls get handled on the main thread. This is removed when the
-        // animation is finished in ::tickAnimation.
-        addMainThreadScrollingReason();
-        return;
-    }
 
     if (m_runState == RunState::PostAnimationCleanup) {
         postAnimationCleanupAndReset();
         return;
     }
 
     if (m_runState == RunState::WaitingToCancelOnCompositor) {
         DCHECK(m_compositorAnimationId);
         abortAnimation();
         postAnimationCleanupAndReset();
@@ skipping 134 matching lines @@
     }
     return true;
 }
 
 DEFINE_TRACE(ScrollAnimator)
 {
     ScrollAnimatorBase::trace(visitor);
 }
 
 } // namespace blink