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

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

 /*
  * Copyright (C) 2009 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 589 matching lines @@
 static String pointerAsString(const void* ptr)
 {
     TextStream ts;
     ts << ptr;
     return ts.release();
 }
 
 std::unique_ptr<JSONObject> GraphicsLayer::layerTreeAsJSON(LayerTreeFlags flags) const
 {
     RenderingContextMap renderingContextMap;
+    if (flags & OutputChildrenAsLayerList) {
+        std::unique_ptr<JSONObject> json = JSONObject::create();
+        std::unique_ptr<JSONArray> layersArray = JSONArray::create();
+        for (auto& child : m_children)
+            child->layersAsJSONArray(flags, renderingContextMap, layersArray.get());
+        json->setArray("layers", std::move(layersArray));
+        return json;
+    }
     return layerTreeAsJSONInternal(flags, renderingContextMap);
 }
 
-std::unique_ptr<JSONObject> GraphicsLayer::layerTreeAsJSONInternal(LayerTreeFlags flags, RenderingContextMap& renderingContextMap) const
+std::unique_ptr<JSONObject> GraphicsLayer::layerAsJSONInternal(LayerTreeFlags flags, RenderingContextMap& renderingContextMap) const
 {
     std::unique_ptr<JSONObject> json = JSONObject::create();
 
     if (flags & LayerTreeIncludesDebugInfo)
         json->setString("this", pointerAsString(this));
 
     json->setString("name", debugName());
 
     if (m_position != FloatPoint())
         json->setArray("position", pointAsJSONArray(m_position));
@@ skipping 83 matching lines @@
         }
         json->setArray("compositingReasons", std::move(compositingReasonsJSON));
 
         std::unique_ptr<JSONArray> squashingDisallowedReasonsJSON = JSONArray::create();
         for (size_t i = 0; i < kNumberOfSquashingDisallowedReasons; ++i) {
             if (m_debugInfo.getSquashingDisallowedReasons() & kSquashingDisallowedReasonStringMap[i].reason)
                 squashingDisallowedReasonsJSON->pushString(debug ? kSquashingDisallowedReasonStringMap[i].description : kSquashingDisallowedReasonStringMap[i].shortName);
         }
         json->setArray("squashingDisallowedReasons", std::move(squashingDisallowedReasonsJSON));
     }
+    return json;
+}
+
+std::unique_ptr<JSONObject> GraphicsLayer::layerTreeAsJSONInternal(LayerTreeFlags flags, RenderingContextMap& renderingContextMap) const
+{
+    std::unique_ptr<JSONObject> json = layerAsJSONInternal(flags, renderingContextMap);
 
     if (m_children.size()) {
         std::unique_ptr<JSONArray> childrenJSON = JSONArray::create();
         for (size_t i = 0; i < m_children.size(); i++)
             childrenJSON->pushObject(m_children[i]->layerTreeAsJSONInternal(flags, renderingContextMap));
         json->setArray("children", std::move(childrenJSON));
     }
 
     return json;
 }
 
+void GraphicsLayer::layersAsJSONArray(LayerTreeFlags flags, RenderingContextMap& renderingContextMap, JSONArray* jsonArray) const
+{
+    jsonArray->pushObject(layerAsJSONInternal(flags, renderingContextMap));
+
+    if (m_children.size()) {
+        for (auto& child : m_children)
+            child->layersAsJSONArray(flags, renderingContextMap, jsonArray);
+    }
+}
+
 String GraphicsLayer::layerTreeAsText(LayerTreeFlags flags) const
 {
     return layerTreeAsJSON(flags)->toPrettyJSONString();
 }
 
 static const cc::Layer* ccLayerForWebLayer(const WebLayer* webLayer)
 {
     return webLayer ? webLayer->ccLayer() : nullptr;
 }
 
@@ skipping 503 matching lines @@
 {
     if (!layer) {
         fprintf(stderr, "Cannot showGraphicsLayerTree for (nil).\n");
         return;
     }
 
     String output = layer->layerTreeAsText(blink::LayerTreeIncludesDebugInfo);
     fprintf(stderr, "%s\n", output.utf8().data());
 }
 #endif