Promote RenderLayers that have a transition on opacity, transform, or filter

Source/core/rendering/RenderLayerCompositor.cpp

 /*
  * Copyright (C) 2009, 2010 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 1509 matching lines @@
         return true;
 
     if (layer->isRootLayer()
         || layer->transform() // note: excludes perspective and transformStyle3D.
         || requiresCompositingForVideo(renderer)
         || requiresCompositingForCanvas(renderer)
         || requiresCompositingForPlugin(renderer)
         || requiresCompositingForFrame(renderer)
         || requiresCompositingForBackfaceVisibilityHidden(renderer)
         || requiresCompositingForAnimation(renderer)
+        || requiresCompositingForTransition(renderer)
         || requiresCompositingForFilters(renderer)
         || requiresCompositingForBlending(renderer)
         || requiresCompositingForPosition(renderer, layer)
         || requiresCompositingForOverflowScrolling(layer)
         || renderer->isTransparent()
         || renderer->hasMask()
         || renderer->hasReflection()
         || renderer->hasFilter())
         return true;
 
@@ skipping 28 matching lines @@
 
     if (requiresCompositingForFrame(renderer))
         directReasons |= CompositingReasonIFrame;
     
     if (requiresCompositingForBackfaceVisibilityHidden(renderer))
         directReasons |= CompositingReasonBackfaceVisibilityHidden;
 
     if (requiresCompositingForAnimation(renderer))
         directReasons |= CompositingReasonAnimation;
 
+    if (requiresCompositingForTransition(renderer))
+        directReasons |= CompositingReasonTransition;
+
     if (requiresCompositingForFilters(renderer))
         directReasons |= CompositingReasonFilters;
 
     if (requiresCompositingForPosition(renderer, layer))
         directReasons |= renderer->style()->position() == FixedPosition ? CompositingReasonPositionFixed : CompositingReasonPositionSticky;
 
     if (requiresCompositingForOverflowScrolling(layer))
         directReasons |= CompositingReasonOverflowScrollingTouch;
 
     if (requiresCompositingForBlending(renderer))
@@ skipping 34 matching lines @@
     
     if (reasons & CompositingReasonBackfaceVisibilityHidden)
         return "backface-visibility: hidden";
 
     if (reasons & CompositingReasonClipsCompositingDescendants)
         return "clips compositing descendants";
 
     if (reasons & CompositingReasonAnimation)
         return "animation";
 
+    if (reasons & CompositingReasonTransition)
+        return "transition";
+
     if (reasons & CompositingReasonFilters)
         return "filters";
 
     if (reasons & CompositingReasonPositionFixed)
         return "position: fixed";
 
     if (reasons & CompositingReasonPositionSticky)
         return "position: sticky";
 
     if (reasons & CompositingReasonOverflowScrollingTouch)
@@ skipping 193 matching lines @@
 
     if (AnimationController* animController = renderer->animation()) {
         return (animController->isRunningAnimationOnRenderer(renderer, CSSPropertyOpacity) && inCompositingMode())
             // <rdar://problem/10907251> - WebKit2 doesn't support CA animations of CI filters on Lion and below
             || animController->isRunningAnimationOnRenderer(renderer, CSSPropertyWebkitFilter)
             || animController->isRunningAnimationOnRenderer(renderer, CSSPropertyWebkitTransform);
     }
     return false;
 }
 
+bool RenderLayerCompositor::requiresCompositingForTransition(RenderObject* renderer) const
+{
+    if (!(m_compositingTriggers & ChromeClient::AnimationTrigger))
+        return false;
+
+    return renderer->style()->transitionForProperty(CSSPropertyOpacity)
+        || renderer->style()->transitionForProperty(CSSPropertyWebkitTransform);

[shawnsingh, 2013/05/15 19:24:43]

Would it work to accelerate filter transitions as well?  Seems like we do that
for animations already.

[ajuma, 2013/05/17 17:21:29]

Done.

+}
+
 CompositingReasons RenderLayerCompositor::subtreeReasonsForCompositing(RenderObject* renderer, bool hasCompositedDescendants, bool has3DTransformedDescendants) const
 {
     CompositingReasons subtreeReasons = CompositingReasonNone;
 
     // FIXME: this seems to be a potentially different layer than the layer for which this was called. May not be an error, but is very confusing.
     RenderLayer* layer = toRenderBoxModelObject(renderer)->layer();
 
     // When a layer has composited descendants, some effects, like 2d transforms, filters, masks etc must be implemented
     // via compositing so that they also apply to those composited descdendants.
     if (hasCompositedDescendants) {
@@ skipping 873 matching lines @@
     info.addMember(m_layerForScrollCorner, "layerForScrollCorner");
 #if ENABLE(RUBBER_BANDING)
     info.addMember(m_layerForOverhangAreas, "layerForOverhangAreas");
     info.addMember(m_contentShadowLayer, "contentShadowLayer");
     info.addMember(m_layerForTopOverhangArea, "layerForTopOverhangArea");
     info.addMember(m_layerForBottomOverhangArea, "layerForBottomOverhangArea");
 #endif
 }
 
 } // namespace WebCore