Add builders for tracing event's structural arguments

cc/trees/single_thread_proxy.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/trees/single_thread_proxy.h"
 
 #include "base/auto_reset.h"
 #include "base/debug/trace_event.h"
 #include "cc/debug/benchmark_instrumentation.h"
 #include "cc/output/context_provider.h"
@@ skipping 351 matching lines @@
       // there as the main thread is not blocked, so any posted tasks inside
       // the swap buffers will execute first.
       BlockingTaskRunner::CapturePostTasks blocked;
 
       layer_tree_host_impl_->SwapBuffers(frame);
     }
     DidSwapFrame();
   }
 }
 
-scoped_ptr<base::Value> SingleThreadProxy::AsValue() const {
-  scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue());
-  {
-    // The following line casts away const modifiers because it is just
-    // setting debug state. We still want the AsValue() function and its
-    // call chain to be const throughout.
-    DebugScopedSetImplThread impl(const_cast<SingleThreadProxy*>(this));
+void SingleThreadProxy::AsValueInto(base::debug::TracedValue* state) const {
+  // The following line casts away const modifiers because it is just
+  // setting debug state. We still want the AsValue() function and its
+  // call chain to be const throughout.
+  DebugScopedSetImplThread impl(const_cast<SingleThreadProxy*>(this));
 
-    state->Set("layer_tree_host_impl",
-               layer_tree_host_impl_->AsValue().release());
-  }
-  return state.PassAs<base::Value>();
+  state->BeginDictionary("layer_tree_host_impl");
+  layer_tree_host_impl_->AsValueInto(state);
+  state->EndDictionary();
 }
 
 void SingleThreadProxy::ForceSerializeOnSwapBuffers() {
   {
     DebugScopedSetImplThread impl(this);
     if (layer_tree_host_impl_->renderer()) {
       DCHECK(!layer_tree_host_->output_surface_lost());
       layer_tree_host_impl_->renderer()->DoNoOp();
     }
   }
@@ skipping 63 matching lines @@
 void SingleThreadProxy::DidSwapFrame() {
   if (next_frame_is_newly_committed_frame_) {
     next_frame_is_newly_committed_frame_ = false;
     layer_tree_host_->DidCommitAndDrawFrame();
   }
 }
 
 bool SingleThreadProxy::CommitPendingForTesting() { return false; }
 
 }  // namespace cc