RenderLayerBacking::startAnimation() return value has incorrect semantic

Source/core/rendering/RenderLayerBacking.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1754 matching lines @@
 bool RenderLayerBacking::startAnimation(double timeOffset, const CSSAnimationData* anim, const KeyframeList& keyframes)
 {
     bool hasTransform = renderer()->isBox() && keyframes.containsProperty(CSSPropertyWebkitTransform);
     IntSize boxSize;
     if (hasTransform)
         boxSize = toRenderBox(renderer())->pixelSnappedBorderBoxRect().size();
     WebAnimations animations(m_animationProvider->startAnimation(timeOffset, anim, keyframes, hasTransform, boxSize));
     if (animations.isEmpty())
         return false;
 
-    bool didAnimate = false;
-    if (animations.m_transformAnimation && m_graphicsLayer->addAnimation(animations.m_transformAnimation.get()))
-        didAnimate = true;
-    if (animations.m_opacityAnimation && m_graphicsLayer->addAnimation(animations.m_opacityAnimation.get()))
-        didAnimate = true;
-    if (animations.m_filterAnimation && m_graphicsLayer->addAnimation(animations.m_filterAnimation.get()))
-        didAnimate = true;
+    bool hasOpacity = keyframes.containsProperty(CSSPropertyOpacity);
+    bool hasFilter = keyframes.containsProperty(CSSPropertyWebkitFilter);
+    int animationId = m_animationProvider->getWebAnimationId(keyframes.animationName());
 
-    return didAnimate;
+    // Animating only some properties of the animation is not supported. So if the
+    // GraphicsLayer rejects any property of the animation, we have to remove the
+    // animation and return false to indicate un-accelerated animation is required.
+    if (hasTransform) {
+        if (!animations.m_transformAnimation || !m_graphicsLayer->addAnimation(animations.m_transformAnimation.get()))
+            return false;
+    }
+    if (hasOpacity) {
+        if (!animations.m_opacityAnimation || !m_graphicsLayer->addAnimation(animations.m_opacityAnimation.get())) {
+            if (hasTransform)
+                m_graphicsLayer->removeAnimation(animationId);
+            return false;
+        }
+    }
+    if (hasFilter) {
+        if (!animations.m_filterAnimation || !m_graphicsLayer->addAnimation(animations.m_filterAnimation.get())) {
+            if (hasTransform || hasOpacity)
+                m_graphicsLayer->removeAnimation(animationId);
+            return false;
+        }
+    }
+    return true;
 }
 
 void RenderLayerBacking::animationPaused(double timeOffset, const String& animationName)
 {
     int animationId = m_animationProvider->getWebAnimationId(animationName);
     if (animationId)
         m_graphicsLayer->pauseAnimation(animationId, timeOffset);
 }
 
 void RenderLayerBacking::animationFinished(const String& animationName)
@@ skipping 146 matching lines @@
     } else if (graphicsLayer == m_scrollingContentsLayer.get()) {
         name = "Scrolling Contents Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace WebCore