Added LayerTreeHostImpl::layerTreeAsJson which serializes a layer tree

cc/layer_tree_host_impl.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layer_tree_host_impl.h"
 
 #include <algorithm>
 
 #include "base/basictypes.h"
 #include "base/debug/trace_event.h"
+#include "base/json/json_writer.h"
 #include "base/stl_util.h"
 #include "cc/append_quads_data.h"
 #include "cc/damage_tracker.h"
 #include "cc/debug_rect_history.h"
 #include "cc/delay_based_time_source.h"
 #include "cc/frame_rate_counter.h"
 #include "cc/gl_renderer.h"
 #include "cc/heads_up_display_layer_impl.h"
 #include "cc/layer_iterator.h"
 #include "cc/layer_tree_host.h"
@@ skipping 1524 matching lines @@
 {
     std::string str;
     if (rootLayer()) {
         str = rootLayer()->layerTreeAsText();
         str +=  "RenderSurfaces:\n";
         dumpRenderSurfaces(&str, 1, rootLayer());
     }
     return str;
 }
 
+std::string LayerTreeHostImpl::layerTreeAsJson() const
+{
+    std::string str;
+    if (rootLayer()) {
+        scoped_ptr<base::Value> json(rootLayer()->layerTreeAsJson());
+        base::JSONWriter::WriteWithOptions(
+            json.get(), base::JSONWriter::OPTIONS_PRETTY_PRINT, &str);
+    }
+    return str;
+}
+
 void LayerTreeHostImpl::dumpRenderSurfaces(std::string* str, int indent, const LayerImpl* layer) const
 {
     if (layer->renderSurface())
         layer->renderSurface()->dumpSurface(str, indent);
 
     for (size_t i = 0; i < layer->children().size(); ++i)
         dumpRenderSurfaces(str, indent, layer->children()[i]);
 }
 
 int LayerTreeHostImpl::sourceAnimationFrameNumber() const
@@ skipping 49 matching lines @@
 
 void LayerTreeHostImpl::UnregisterAnimationController(LayerAnimationController* controller) {
 #if !defined(NDEBUG)
     if (ContainsKey(m_allAnimationControllers, controller))
         m_allAnimationControllers.erase(controller);
 #endif
     DidDeactivateAnimationController(controller);
 }
 
 }  // namespace cc