Change VideoFrameCompositor events to be async.

media/blink/video_frame_compositor.cc

 // Copyright 2014 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 "media/blink/video_frame_compositor.h"
 
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
 #include "base/time/default_tick_clock.h"
 #include "base/trace_event/trace_event.h"
@@ skipping 87 matching lines @@
   DCHECK(compositor_task_runner_->BelongsToCurrentThread());
   return CallRender(deadline_min, deadline_max, false);
 }
 
 bool VideoFrameCompositor::HasCurrentFrame() {
   DCHECK(compositor_task_runner_->BelongsToCurrentThread());
   return static_cast<bool>(current_frame_);
 }
 
 void VideoFrameCompositor::Start(RenderCallback* callback) {
-  TRACE_EVENT0("media,rail", "VideoFrameCompositor::Start");
+  TRACE_EVENT_ASYNC_BEGIN0("media,rail", "VideoPlayback",
+                           static_cast<const void*>(this));
 
   // Called from the media thread, so acquire the callback under lock before
   // returning in case a Stop() call comes in before the PostTask is processed.
   base::AutoLock lock(callback_lock_);
   DCHECK(!callback_);
   callback_ = callback;
   compositor_task_runner_->PostTask(
       FROM_HERE, base::Bind(&VideoFrameCompositor::OnRendererStateUpdate,
                             base::Unretained(this), true));
 }
 
 void VideoFrameCompositor::Stop() {
-  TRACE_EVENT0("media,rail", "VideoFrameCompositor::Stop");
+  TRACE_EVENT_ASYNC_END0("media,rail", "VideoPlayback",
+                         static_cast<const void*>(this));
 
   // Called from the media thread, so release the callback under lock before
   // returning to avoid a pending UpdateCurrentFrame() call occurring before
   // the PostTask is processed.
   base::AutoLock lock(callback_lock_);
   DCHECK(callback_);
   callback_ = nullptr;
   compositor_task_runner_->PostTask(
       FROM_HERE, base::Bind(&VideoFrameCompositor::OnRendererStateUpdate,
                             base::Unretained(this), false));
@@ skipping 107 matching lines @@
   last_interval_ = deadline_max - deadline_min;
 
   // Restart the background rendering timer whether we're background rendering
   // or not; in either case we should wait for |kBackgroundRenderingTimeoutMs|.
   if (background_rendering_enabled_)
     background_rendering_timer_.Reset();
   return new_frame || had_new_background_frame;
 }
 
 }  // namespace media