Animation: Cancel same-property animations on compositor

Source/core/animation/AnimationPlayer.cpp

Index: Source/core/animation/AnimationPlayer.cpp
diff --git a/Source/core/animation/AnimationPlayer.cpp b/Source/core/animation/AnimationPlayer.cpp
index b3ad782e389f17110f27b535006eead7da0c4ec4..d400e1bdf3c1894e04b3451efde6f89e267c5050 100644
--- a/Source/core/animation/AnimationPlayer.cpp
+++ b/Source/core/animation/AnimationPlayer.cpp
@@ -246,8 +246,11 @@ void AnimationPlayer::preCommit(int compositorGroup, bool startOnCompositor)
 
     if (shouldStart) {
         m_compositorGroup = compositorGroup;
-        if (startOnCompositor && maybeStartAnimationOnCompositor()) {
-            m_compositorState = adoptPtr(new CompositorState(*this));
+        if (startOnCompositor) {
+            if (maybeStartAnimationOnCompositor())
+                m_compositorState = adoptPtr(new CompositorState(*this));
+            else
+                cancelIncompatibleAnimationsOnCompositor();
         }
     }
 }
@@ -331,6 +334,15 @@ void AnimationPlayer::notifyStartTime(double timelineTime)
     }
 }
 
+bool AnimationPlayer::affects(const Element& element, CSSPropertyID property) const
+{
+    if (!m_content || !m_content->isAnimation())
+        return false;
+
+    const Animation* animation = toAnimation(m_content.get());
+    return (animation->target() == &element) && animation->affects(property);
+}
+
 double AnimationPlayer::calculateStartTime(double currentTime) const
 {
     return m_timeline->effectiveTime() - currentTime / m_playbackRate;
@@ -690,6 +702,18 @@ void AnimationPlayer::setCompositorPending(bool sourceChanged)
     }
 }
 
+void AnimationPlayer::cancelAnimationOnCompositor()
+{
+    if (hasActiveAnimationsOnCompositor())
+        toAnimation(m_content.get())->cancelAnimationOnCompositor();
+}
+
+void AnimationPlayer::cancelIncompatibleAnimationsOnCompositor()
+{
+    if (m_content && m_content->isAnimation())
+        toAnimation(m_content.get())->cancelIncompatibleAnimationsOnCompositor();
+}
+
 bool AnimationPlayer::hasActiveAnimationsOnCompositor()
 {
     if (!m_content || !m_content->isAnimation())
@@ -698,12 +722,6 @@ bool AnimationPlayer::hasActiveAnimationsOnCompositor()
     return toAnimation(m_content.get())->hasActiveAnimationsOnCompositor();
 }
 
-void AnimationPlayer::cancelAnimationOnCompositor()
-{
-    if (hasActiveAnimationsOnCompositor())
-        toAnimation(m_content.get())->cancelAnimationOnCompositor();
-}
-
 bool AnimationPlayer::update(TimingUpdateReason reason)
 {
     if (!m_timeline)
@@ -806,7 +824,6 @@ AnimationPlayer::PlayStateUpdateScope::~PlayStateUpdateScope()
     if (oldPlayState != newPlayState) {
         bool wasActive = oldPlayState == Pending || oldPlayState == Running;
         bool isActive = newPlayState == Pending || newPlayState == Running;
-
         if (!wasActive && isActive)
             TRACE_EVENT_NESTABLE_ASYNC_BEGIN1("blink.animations," TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "Animation", m_player, "data", InspectorAnimationEvent::data(*m_player));
         else if (wasActive && !isActive)