Revert of Revert of Always post buffering state updates since they may change sink state. (patchset #1 id:1 of https://codereview.chromium.org/1159573005/)
Revert of Revert of Always post buffering state updates since they may change sink state. (patchset #1 id:1 of https://codereview.chromium.org/1159573005/)

Reason for revert:
The original patch was innocent.

Original issue's description:
> Revert of Always post buffering state updates since they may change sink state. (patchset #1 id:1 of https://codereview.chromium.org/1161463006/)
>
> Reason for revert:
> Speculative revert for Blink layout tests crashes on Nexus 4:
> http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Android%20%28Nexus4%29
> (SEGV on CrGpuMain thread is observed)
>
> Sorry if my guess is not correct; there wasn't
> a clear signal to identify the culprit.
>
> Original issue's description:
> > Always post buffering state updates since they may change sink state.
> >
> > The lock must never be held when OnTimeStateChanged() is calling into
> > the VideoRendererSink or we can deadlock the compositor thread.
> >
> > With video-only playback occurs a buffering state change for underflow
> > would immediately invoke OnTimeStateChanged(false) which would try to
> > stop the VideoRendererSink under lock.
> >
> > BUG=496466
> > TEST=video only playback doesn't deadlock.
> >
> > Committed: https://crrev.com/9d8a53f3bf01aed28abbd1f9a713a25362c0d158
> > Cr-Commit-Position: refs/heads/master@{#332772}
>
> TBR=xhwang@chromium.org,dalecurtis@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=496466
>
> Committed: https://crrev.com/9fc2a61ce37405635c5528db9d5773c4f30b592d
> Cr-Commit-Position: refs/heads/master@{#332808}

TBR=xhwang@chromium.org,dalecurtis@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=496466

Review URL: https://codereview.chromium.org/1157573009

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#332812}

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