Add tracing AutoOpenCloseEvent.

media/blink/video_frame_compositor.cc

Index: media/blink/video_frame_compositor.cc
diff --git a/media/blink/video_frame_compositor.cc b/media/blink/video_frame_compositor.cc
index 544f7098701d481c2358c2493d2f59aae52d5256..75bb0ff12f965349b57fe562d6e423c6160bff12 100644
--- a/media/blink/video_frame_compositor.cc
+++ b/media/blink/video_frame_compositor.cc
@@ -7,6 +7,7 @@
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
 #include "base/time/default_tick_clock.h"
+#include "base/trace_event/auto_open_close_event.h"
 #include "base/trace_event/trace_event.h"
 #include "media/base/video_frame.h"
 
@@ -35,7 +36,10 @@ VideoFrameCompositor::VideoFrameCompositor(
       new_background_frame_(false),
       // Assume 60Hz before the first UpdateCurrentFrame() call.
       last_interval_(base::TimeDelta::FromSecondsD(1.0 / 60)),
-      callback_(nullptr) {
+      callback_(nullptr),
+      auto_open_close_(base::trace_event::AutoOpenCloseEvent::Type::ASYNC,
+                       "media,rail",
+                       "VideoPlayback") {
   background_rendering_timer_.SetTaskRunner(compositor_task_runner_);
 }
 
@@ -105,8 +109,7 @@ bool VideoFrameCompositor::HasCurrentFrame() {
 }
 
 void VideoFrameCompositor::Start(RenderCallback* callback) {
-  TRACE_EVENT_ASYNC_BEGIN0("media,rail", "VideoPlayback",
-                           static_cast<const void*>(this));
+  auto_open_close_.Begin();
 
   // 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.
@@ -119,8 +122,7 @@ void VideoFrameCompositor::Start(RenderCallback* callback) {
 }
 
 void VideoFrameCompositor::Stop() {
-  TRACE_EVENT_ASYNC_END0("media,rail", "VideoPlayback",
-                         static_cast<const void*>(this));
+  auto_open_close_.End();
 
   // Called from the media thread, so release the callback under lock before
   // returning to avoid a pending UpdateCurrentFrame() call occurring before