Making BeginFrameArgs work with TRACE_EVENT system.

cc/output/begin_frame_args.cc

 // Copyright 2013 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 "base/json/json_writer.h"
 #include "cc/output/begin_frame_args.h"
 #include "ui/gfx/frame_time.h"
 
 namespace cc {
 
 BeginFrameArgs::BeginFrameArgs()
   : frame_time(base::TimeTicks()),
     deadline(base::TimeTicks()),
     interval(base::TimeDelta::FromMicroseconds(-1)) {
 }
 
 BeginFrameArgs::BeginFrameArgs(base::TimeTicks frame_time,
                                base::TimeTicks deadline,
                                base::TimeDelta interval)
   : frame_time(frame_time),
     deadline(deadline),
     interval(interval)
 {}
 
 BeginFrameArgs BeginFrameArgs::Create(base::TimeTicks frame_time,
                                       base::TimeTicks deadline,
                                       base::TimeDelta interval) {
   return BeginFrameArgs(frame_time, deadline, interval);
 }
 
+scoped_ptr<base::Value> BeginFrameArgs::StateAsValue() const {
+  scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue);
+  state->SetString("type", "BeginFrameArgs");
+  state->SetDouble("frame_time_us", frame_time.ToInternalValue());
+  state->SetDouble("deadline_us", deadline.ToInternalValue());
+  state->SetDouble("interval_us", interval.InMicroseconds());
+  return state.PassAs<base::Value>();
+}
+
 BeginFrameArgs BeginFrameArgs::CreateForSynchronousCompositor() {
   // For WebView/SynchronousCompositor, we always want to draw immediately,
   // so we set the deadline to 0 and guess that the interval is 16 milliseconds.
   return BeginFrameArgs(gfx::FrameTime::Now(),
                         base::TimeTicks(),
                         DefaultInterval());
 }
 
 BeginFrameArgs BeginFrameArgs::CreateForTesting() {
   base::TimeTicks now = gfx::FrameTime::Now();
@@ skipping 21 matching lines @@
 
 base::TimeDelta BeginFrameArgs::DefaultInterval() {
   return base::TimeDelta::FromMicroseconds(16666);
 }
 
 base::TimeDelta BeginFrameArgs::DefaultRetroactiveBeginFramePeriod() {
   return base::TimeDelta::FromMicroseconds(4444);
 }
 
 }  // namespace cc