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 2483 matching lines @@
             continue; // FIXME: Can this happen?
         if (HTMLFrameOwnerElement* ownerElement = child->document()->ownerElement()) {
             DeprecatedScheduleStyleRecalcDuringCompositingUpdate marker(ownerElement->document().lifecycle());
             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()) {
+        ownerElement->document().renderView()->compositor()->setNeedsToRecomputeCompositingRequirements();
         DeprecatedScheduleStyleRecalcDuringCompositingUpdate marker(ownerElement->document().lifecycle());
         ownerElement->scheduleLayerUpdate();
     }
 }
 
 bool RenderLayerCompositor::layerHas3DContent(const RenderLayer* layer) const
 {
     const RenderStyle* style = layer->renderer()->style();
     RenderLayerStackingNode* stackingNode = const_cast<RenderLayer*>(layer)->stackingNode();
 
@@ skipping 147 matching lines @@
     } else if (graphicsLayer == m_scrollLayer.get()) {
         name = "Frame Scrolling Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace WebCore