Avoid unnecessary post task during frame delivery.

content/common/gpu/media/android_video_decode_accelerator.cc

Index: content/common/gpu/media/android_video_decode_accelerator.cc
diff --git a/content/common/gpu/media/android_video_decode_accelerator.cc b/content/common/gpu/media/android_video_decode_accelerator.cc
index 55b1855a546d482fd89f87b95d6361c0d89e88ab..36c11c5e2e5dc8c1d3a3729894849fd52781dfea 100644
--- a/content/common/gpu/media/android_video_decode_accelerator.cc
+++ b/content/common/gpu/media/android_video_decode_accelerator.cc
@@ -829,19 +829,20 @@ void AndroidVideoDecodeAccelerator::SendDecodedFrameToClient(
     size_changed = true;
   }
 
-  // Connect the PictureBuffer to the decoded frame, via whatever
-  // mechanism the strategy likes.
-  strategy_->UseCodecBufferForPictureBuffer(codec_buffer_index, i->second);
-
   const bool allow_overlay = strategy_->ArePicturesOverlayable();
-
   media::Picture picture(picture_buffer_id, bitstream_id, gfx::Rect(size_),
                          allow_overlay);
   picture.set_size_changed(size_changed);
 
-  base::MessageLoop::current()->PostTask(
-      FROM_HERE, base::Bind(&AndroidVideoDecodeAccelerator::NotifyPictureReady,
-                            weak_this_factory_.GetWeakPtr(), picture));
+  // Notify picture ready before calling UseCodecBufferForPictureBuffer() since
+  // that process may be slow and shouldn't delay delivery of the frame to the
+  // renderer. The picture is only used on the same thread as this method is
+  // called, so it is safe to do this.
+  NotifyPictureReady(picture);

[liberato (no reviews please), 2016/04/25 19:58:22]

how much time does this buy?

[DaleCurtis, 2016/04/25 22:32:22]

You mean not posting or the reorder? Combined this saves ~1.5ms to ~3.5ms
depending on if we release to the back buffer or not.

+
+  // Connect the PictureBuffer to the decoded frame, via whatever mechanism the
+  // strategy likes.
+  strategy_->UseCodecBufferForPictureBuffer(codec_buffer_index, i->second);
 }
 
 void AndroidVideoDecodeAccelerator::Decode(