Avoid requiring a recalc to update compositing state for iframes

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 2467 matching lines @@
         return;
     Frame& frame = m_renderView->frameView()->frame();
 
     for (Frame* child = frame.tree().firstChild(); child; child = child->tree().traverseNext(&frame)) {
         if (child->document() && child->document()->ownerElement())
             child->document()->ownerElement()->scheduleLayerUpdate();
     }
 
     // Compositing also affects the answer to RenderIFrame::requiresAcceleratedCompositing(), so
     // we need to schedule a style recalc in our parent document.
-    if (HTMLFrameOwnerElement* ownerElement = m_renderView->document().ownerElement())
+    if (HTMLFrameOwnerElement* ownerElement = m_renderView->document().ownerElement()) {
+        ownerElement->document().renderView()->compositor()->setNeedsToRecomputeCompositingRequirements();
         ownerElement->scheduleLayerUpdate();

[shawnsingh, 2014/02/06 13:32:16]

I'm curious what else does scheduleLayerUpdate do other than flag a
setNeedsRecalcStyle?

If it doesn't do anything meaningfully significant w.r.t. iframe compositing
changes (and if it does, it shouldn't), then I think we could just remove this
entire function, and replace it with a much simpler
setNeedsToRecoputeCompositingRequirements like you added here.

[dstockwell, 2014/02/07 03:22:03]

That's all it does. I think we can remove it, but I think we should do it in a
follow up so that this more surgical change can be merged to M33.

+    }
 }
 
 bool RenderLayerCompositor::layerHas3DContent(const RenderLayer* layer) const
 {
     const RenderStyle* style = layer->renderer()->style();
     RenderLayerStackingNode* stackingNode = const_cast<RenderLayer*>(layer)->stackingNode();
 
     if (style &&
         (style->transformStyle3D() == TransformStyle3DPreserve3D ||
          style->hasPerspective() ||
@@ skipping 139 matching lines @@
     } else if (graphicsLayer == m_scrollLayer.get()) {
         name = "Frame Scrolling Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace WebCore