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..0be43ba524944de74acb19dd4a6e0d4772eb662a 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"
 
@@ -35,14 +36,21 @@ 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_(nullptr) {
   background_rendering_timer_.SetTaskRunner(compositor_task_runner_);
+  constructor_task_runner_ = base::ThreadTaskRunnerHandle::Get();
+  auto_open_close_ = new base::trace_event::AutoOpenCloseEvent(

[Primiano Tucci (use gerrit), 2016/10/12 16:36:50]

raw pointers with manual new/delete are discouraged. Why this isn't a
scoped_ptr?

[alexandermont, 2016/10/13 19:15:53]

Changed to unique ptr

+      base::trace_event::AutoOpenCloseEvent::Type::ASYNC, "media,rail",
+      "VideoPlayback");
 }
 
 VideoFrameCompositor::~VideoFrameCompositor() {
   DCHECK(compositor_task_runner_->BelongsToCurrentThread());
   DCHECK(!callback_);
   DCHECK(!rendering_);
+  if (auto_open_close_)
+    delete auto_open_close_;

[benjhayden, 2016/10/12 03:05:54]

This will only work if VFC is created on the compositor_task_runner thread.

[Primiano Tucci (use gerrit), 2016/10/12 16:36:50]

this should be just a auto_open_close.reset()

   if (client_)
     client_->StopUsingProvider();
 }
@@ -105,8 +113,9 @@ bool VideoFrameCompositor::HasCurrentFrame() {
 }
 
 void VideoFrameCompositor::Start(RenderCallback* callback) {
-  TRACE_EVENT_ASYNC_BEGIN0("media,rail", "VideoPlayback",
-                           static_cast<const void*>(this));
+  constructor_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&base::trace_event::AutoOpenCloseEvent::Begin,
+                            base::Unretained(auto_open_close_)));
 
   // 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 +128,9 @@ void VideoFrameCompositor::Start(RenderCallback* callback) {
 }
 
 void VideoFrameCompositor::Stop() {
-  TRACE_EVENT_ASYNC_END0("media,rail", "VideoPlayback",
-                         static_cast<const void*>(this));
+  constructor_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&base::trace_event::AutoOpenCloseEvent::End,
+                            base::Unretained(auto_open_close_)));
 
   // Called from the media thread, so release the callback under lock before
   // returning to avoid a pending UpdateCurrentFrame() call occurring before