WebKit merge 40722:40785 (part 1)

third_party/WebKit/WebCore/rendering/RenderLayerCompositor.cpp

 /*
  * Copyright (C) 2009 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 435 matching lines @@
         if (m_rootPlatformLayer)
             m_rootPlatformLayer->addChild(layerAnchor);
     }
 }
 
 void RenderLayerCompositor::rebuildCompositingLayerTree(RenderLayer* layer, struct CompositingState& ioCompState)
 {
     updateLayerCompositingState(layer, StyleDifferenceEqual);
 
     // host the document layer in the RenderView's root layer
-    if (layer->isDocumentLayer())
+    if (layer->isRootLayer())
         parentInRootLayer(layer);
 
     CompositingState childState = ioCompState;
     if (layer->isComposited())
         childState.m_compositingAncestor = layer;
 
 #ifndef NDEBUG
     ++childState.m_depth;
 #endif
 
@@ skipping 163 matching lines @@
 
 // Note: this specifies whether the RL needs a compositing layer for intrinsic reasons.
 // Use needsToBeComposited() to determine if a RL actually needs a compositing layer.
 // static
 bool RenderLayerCompositor::requiresCompositingLayer(const RenderLayer* layer) const
 {
     // FIXME: cache the result of these tests?
 #if VERBOSE_COMPOSITINGLAYER
     bool gotReason = false;
 
-    if (!gotReason && inCompositingMode() && layer->isDocumentLayer()) {
+    if (!gotReason && inCompositingMode() && layer->isRootLayer()) {
         fprintf(stderr, "RenderLayer %p requires compositing layer because: it's the document root\n", layer);
         gotReason = true;
     }
     
     if (!gotReason && requiresCompositingLayerForTransform(layer->renderer())) {
         fprintf(stderr, "RenderLayer %p requires compositing layer because: it has 3d transform, perspective, backface, or animating transform\n", layer);
         gotReason = true;
     }
 
     if (!gotReason && clipsCompositingDescendants(layer)) {
         fprintf(stderr, "RenderLayer %p requires compositing layer because: it has overflow clip\n", layer);
         gotReason = true;
     }
 
     if (!gotReason && requiresCompositingForAnimation(layer)) {
         fprintf(stderr, "RenderLayer %p requires compositing layer because: it has a running transition for opacity or transform\n", layer);
         gotReason = true;
     }
     
     if (!gotReason)
         fprintf(stderr, "RenderLayer %p does not require compositing layer\n", layer);
 #endif
 
-    // the root layer always has a compositing layer (for now).
-    return (inCompositingMode() && layer->isDocumentLayer()) ||
+    // The root layer always has a compositing layer, but it may not have backing.
+    return (inCompositingMode() && layer->isRootLayer()) ||
              requiresCompositingLayerForTransform(layer->renderer()) ||
              clipsCompositingDescendants(layer) ||
              requiresCompositingForAnimation(layer);
 }
 
 // Return true if the given layer has some ancestor in the RenderLayer hierarchy that clips,
 // up to the enclosing compositing ancestor. This is required because compositing layers are parented
 // according to the z-order hierarchy, yet clipping goes down the renderer hierarchy.
 // Thus, a RenderLayer can be clipped by a RenderLayer that is an ancestor in the renderer hierarchy,
 // but a sibling in the z-order hierarchy.
@@ skipping 62 matching lines @@
     // Need to clip to prevent transformed content showing outside this frame
     m_rootPlatformLayer->setMasksToBounds(true);
     
     didMoveOnscreen();
 }
 
 } // namespace WebCore
 
 #endif // USE(ACCELERATED_COMPOSITING)