Fix a bogus assertion in CLM

Source/core/rendering/compositing/CompositedLayerMapping.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 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 1870 matching lines @@
 {
     unsigned previousRequiresOwnBackingStoreForAncestorReasons = m_requiresOwnBackingStoreForAncestorReasons;
     bool previousPaintsIntoCompositedAncestor = paintsIntoCompositedAncestor();
     bool canPaintIntoAncestor = compositingAncestorLayer
         && (compositingAncestorLayer->compositedLayerMapping()->mainGraphicsLayer()->drawsContent()
             || compositingAncestorLayer->compositedLayerMapping()->paintsIntoCompositedAncestor());
 
     if (paintsIntoCompositedAncestor() != previousPaintsIntoCompositedAncestor)
         compositor()->paintInvalidationOnCompositingChange(&m_owningLayer);
 
+    // FIXME: this is bogus. We need to make this assignment before the check above.
     m_requiresOwnBackingStoreForAncestorReasons = !canPaintIntoAncestor;
 
     return m_requiresOwnBackingStoreForAncestorReasons != previousRequiresOwnBackingStoreForAncestorReasons;
 }
 
 bool CompositedLayerMapping::updateRequiresOwnBackingStoreForIntrinsicReasons()
 {
     unsigned previousRequiresOwnBackingStoreForIntrinsicReasons = m_requiresOwnBackingStoreForIntrinsicReasons;
     bool previousPaintsIntoCompositedAncestor = paintsIntoCompositedAncestor();
     RenderObject* renderer = m_owningLayer.renderer();
@@ skipping 107 matching lines @@
 
     // Convert from ancestor to local coordinates.
     IntSize ancestorToLocalOffset = paintInfo.offsetFromRenderer - ancestorPaintInfo->offsetFromRenderer;
     parentClipRect.move(ancestorToLocalOffset);
     return parentClipRect;
 }
 
 void CompositedLayerMapping::doPaintTask(const GraphicsLayerPaintInfo& paintInfo, const PaintLayerFlags& paintLayerFlags, GraphicsContext* context,
     const IntRect& clip) // In the coords of rootLayer.
 {
-    if (paintsIntoCompositedAncestor()) {
-        ASSERT_NOT_REACHED();
-        return;
-    }
+    RELEASE_ASSERT(paintInfo.renderLayer->compositingState() == PaintsIntoGroupedBacking || !paintsIntoCompositedAncestor());
 
     FontCachePurgePreventer fontCachePurgePreventer;
 
     // Note carefully: in theory it is appropriate to invoke context->save() here
     // and restore the context after painting. For efficiency, we are assuming that
     // it is equivalent to manually undo this offset translation, which means we are
     // assuming that the context's space was not affected by the RenderLayer
     // painting code.
 
     IntSize offset = paintInfo.offsetFromRenderer;
@@ skipping 248 matching lines @@
     } else if (graphicsLayer == m_scrollingBlockSelectionLayer.get()) {
         name = "Scrolling Block Selection Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink