[SPv2] Introduce an option to output the GraphicsLayer tree as a flat layer list.

third_party/WebKit/Source/platform/graphics/GraphicsLayer.h

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. 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
@@ skipping 272 matching lines @@
     void updateLayerIsDrawable();
     void updateContentsRect();
 
     void setContentsTo(WebLayer*);
     void setupContentsLayer(WebLayer*);
     void clearContentsLayerIfUnregistered();
     WebLayer* contentsLayerIfRegistered();
 
     typedef HashMap<int, int> RenderingContextMap;
     std::unique_ptr<JSONObject> layerTreeAsJSONInternal(LayerTreeFlags, RenderingContextMap&) const;
+    // Outputs the layer tree rooted at |this| as a JSON array, in paint order.
+    void layersAsJSONArray(LayerTreeFlags, RenderingContextMap&, JSONArray*) const;
+    std::unique_ptr<JSONObject> layerAsJSONInternal(LayerTreeFlags, RenderingContextMap&) const;
 
     sk_sp<SkPicture> capturePicture();
     void checkPaintUnderInvalidations(const SkPicture&);
 
     GraphicsLayerClient* m_client;
 
     // Offset from the owning layoutObject
     DoubleSize m_offsetFromLayoutObject;
 
     // Position is relative to the parent GraphicsLayer
@@ skipping 58 matching lines @@
 };
 
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the blink namespace for ease of invocation from gdb.
 void PLATFORM_EXPORT showGraphicsLayerTree(const blink::GraphicsLayer*);
 #endif
 
 #endif // GraphicsLayer_h