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 2450 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();
+    }

[abarth-chromium, 2014/02/06 03:27:50]

I ran into this same function when working on putting the layout states into the
DocumentLifecycle state machine:

https://codereview.chromium.org/156413002

The problem with this function is that it schedules a style recalc while layout
is on the stack.  Now that we're more careful to only do layout when we're about
to put up a frame, the style recalc doesn't actually happen until the next
frame.  I'm not sure whether that's the cause of the bug you're seeing, but it's
one way that we might put up a frame while we're in an inconsistent state.

[dstockwell, 2014/02/06 03:36:19]

I think that's the main reason this is broken at head. I believe with these
changes it should be possible to remove the recalc request here.

 }
 
 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