Remove the CompositedLayerMappingPtr smart ptr.

Source/core/rendering/RenderLayer.h

 /*
  * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
@@ skipping 38 matching lines @@
 #include "core/rendering/LayerPaintingInfo.h"
 #include "core/rendering/RenderBox.h"
 #include "core/rendering/RenderLayerBlendInfo.h"
 #include "core/rendering/RenderLayerClipper.h"
 #include "core/rendering/RenderLayerFilterInfo.h"
 #include "core/rendering/RenderLayerReflectionInfo.h"
 #include "core/rendering/RenderLayerRepainter.h"
 #include "core/rendering/RenderLayerScrollableArea.h"
 #include "core/rendering/RenderLayerStackingNode.h"
 #include "core/rendering/RenderLayerStackingNodeIterator.h"
-#include "core/rendering/compositing/CompositedLayerMappingPtr.h"
 #include "platform/graphics/CompositingReasons.h"
 #include "wtf/OwnPtr.h"
 
 namespace blink {
 
 class FilterEffectRenderer;
 class FilterOperations;
 class HitTestRequest;
 class HitTestResult;
 class HitTestingTransformState;
@@ skipping 229 matching lines @@
     void* operator new(size_t);
     // Only safe to call from RenderLayerModelObject::destroyLayer()
     void operator delete(void*);
 
     CompositingState compositingState() const;
 
     // This returns true if our document is in a phase of its lifestyle during which
     // compositing state may legally be read.
     bool isAllowedToQueryCompositingState() const;
 
-    // NOTE: Don't call these compositing methods unless you know what you are doing and are sure it is the best approach!
-    CompositedLayerMappingPtr compositedLayerMapping() const;
-    CompositedLayerMappingPtr ensureCompositedLayerMapping();
+    // Don't null check this.
+    CompositedLayerMapping* compositedLayerMapping() const;
+    // FIXME: This should return a reference.
+    CompositedLayerMapping* ensureCompositedLayerMapping();
     GraphicsLayer* graphicsLayerBacking() const;
     GraphicsLayer* graphicsLayerBackingForScrolling() const;
     // NOTE: If you are using hasCompositedLayerMapping to determine the state of compositing for this layer,
     // (and not just to do bookkeeping related to the mapping like, say, allocating or deallocating a mapping),
     // then you may have incorrect logic. Use compositingState() instead.
+    // FIXME: This is identical to null checking compositedLayerMapping(), why not just call that?
     bool hasCompositedLayerMapping() const { return m_compositedLayerMapping.get(); }

[abarth-chromium, 2014/08/08 15:34:19]

Shawn's idea was to make all the call sites that wanted to null-check
m_compositedLayerMapping explicitly call a function that was greppable in order
to make it easier to implement squashing.

[chrishtr, 2014/08/08 16:11:42]

Let's get rid of hasCompositedLayerMapping in this CL.

     void clearCompositedLayerMapping(bool layerBeingDestroyed = false);
     CompositedLayerMapping* groupedMapping() const { return m_groupedMapping; }
     void setGroupedMapping(CompositedLayerMapping* groupedMapping, bool layerBeingDestroyed = false);
 
     bool hasCompositedMask() const;
     bool hasCompositedClippingMask() const;
     bool needsCompositedScrolling() const { return m_scrollableArea && m_scrollableArea->needsCompositedScrolling(); }
 
     bool clipsCompositingDescendantsWithBorderRadius() const;
 
@@ skipping 444 matching lines @@
 
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showLayerTree(const blink::RenderLayer*);
 void showLayerTree(const blink::RenderObject*);
 #endif
 
 #endif // RenderLayer_h