Merge 219225 "Run |demuxer_| related tasks in the media thread i..."

Merge 219225 "Run |demuxer_| related tasks in the media thread i..."

> Run |demuxer_| related tasks in the media thread in GTV.
> 
> - We found that the reading from |demuxer_| and its read-callback loops run very slowly, in the heavy load situation in the render thread.
> to improve the response time of the readings, we run tasks related to |demuxer_| in the media thread.
> 
> BUG=268208
> 
> Review URL: https://chromiumcodereview.appspot.com/22875030

TBR=ycheo@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=220851

[qinmin, 2013-09-02 18:53:36]

Committed patchset #1 manually as r220851.

[ycheo (away), 2013-09-03 03:46:25]

@Min,

I found that this merge break the build of m30 branch in Chrome for Android &
TV:
http://master.chrome.corp.google.com:8000/builders/android/builds/1555
http://master.chrome.corp.google.com:8000/builders/android-tv/builds/317

The reason is the member variable, |media_source_opened_cb_| didn't exist when
m30 branch was out.

I think some reverts of lines can fix this breakage.

https://codereview.chromium.org/23875003/diff/1/content/renderer/media/androi...
File content/renderer/media/android/media_source_delegate.cc (right):

https://codereview.chromium.org/23875003/diff/1/content/renderer/media/androi...
content/renderer/media/android/media_source_delegate.cc:160:
DCHECK(!media_source_opened_cb.is_null());
This line should be reverted to OLD-L129.

https://codereview.chromium.org/23875003/diff/1/content/renderer/media/androi...
content/renderer/media/android/media_source_delegate.cc:161:
media_source_opened_cb_ = media_source_opened_cb;
This line should be reverted to OLD-L130.

https://codereview.chromium.org/23875003/diff/1/content/renderer/media/androi...
content/renderer/media/android/media_source_delegate.cc:733: if
(media_source_opened_cb_.is_null())
This line should be reverted to OLD-L604.