Set geometry dirty bits on composited layer mappings when updating squashed layers.

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 2046 matching lines @@
     if (nextSquashedLayerIndex < m_squashedLayers.size()) {
         if (!paintInfo.isEquivalentForSquashing(m_squashedLayers[nextSquashedLayerIndex])) {
             updatedAssignment = true;
         }
         m_squashedLayers[nextSquashedLayerIndex] = paintInfo;
     } else {
         m_squashedLayers.append(paintInfo);
         updatedAssignment = true;
     }
     layer->setGroupedMapping(this);
+    setNeedsGeometryUpdate();

[abarth-chromium, 2014/03/17 17:17:03]

Should we move this call inside setGroupedMapping?  Don't if the grouped mapping
was non-zero before, don't we need to dirty the old composited layer mapping
too?

[chrishtr, 2014/03/17 18:10:55]

Done.

     return updatedAssignment;
 }
 
 void CompositedLayerMapping::removeRenderLayerFromSquashingGraphicsLayer(const RenderLayer* layer)
 {
     size_t layerIndex = kNotFound;
 
     for (size_t i = 0; i < m_squashedLayers.size(); ++i) {
         if (m_squashedLayers[i].renderLayer == layer) {
             layerIndex = i;
@@ skipping 50 matching lines @@
     } else if (graphicsLayer == m_scrollingContentsLayer.get()) {
         name = "Scrolling Contents Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace WebCore