Making BeginFrameArgs work with TRACE_EVENT system.

cc/output/begin_frame_args.h

 // 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.
 
 #ifndef CC_OUTPUT_BEGIN_FRAME_ARGS_H_
 #define CC_OUTPUT_BEGIN_FRAME_ARGS_H_
 
 #include "base/time/time.h"
+#include "base/values.h"
 #include "cc/base/cc_export.h"
 
 namespace cc {
 
 struct CC_EXPORT BeginFrameArgs {
   // Creates an invalid set of values.
   BeginFrameArgs();
 
   // You should be able to find all instances where a BeginFrame has been
   // created by searching for "BeginFrameArgs::Create".
@@ skipping 13 matching lines @@
   static base::TimeDelta DefaultInterval();
 
   // This is the default amount of time after the frame_time to retroactively
   // send a BeginFrame that had been skipped. This only has an effect if the
   // deadline has passed, since the deadline is also used to trigger BeginFrame
   // retroactively.
   static base::TimeDelta DefaultRetroactiveBeginFramePeriod();
 
   bool IsValid() const { return interval >= base::TimeDelta(); }
 
+  scoped_ptr<base::Value> AsValue() const;
+
   base::TimeTicks frame_time;
   base::TimeTicks deadline;
   base::TimeDelta interval;
 
  private:
   BeginFrameArgs(base::TimeTicks frame_time,
                  base::TimeTicks deadline,
                  base::TimeDelta interval);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_BEGIN_FRAME_ARGS_H_