Cherry pick: Don't process pending prefetch events if we fail to create video decoder job

The fix has been cherry pick to M34 in upstream.

BUG: 13183769

Upstream bug description:
    In the current logic, we continue to process prefetch requests if video decoder job fails to
    However, that may lead to a NPE because we do not do null check on video_decoder_job_ in our
    Since StartInternal() won't do anything if video decoder job is null, we can return early whe
    Playback will continue once a non-empty surface is passed to MSP.

    BUG=343508

    Review URL: https://codereview.chromium.org/171233007

    git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252489 0039d316-1c4b-4281-b951-d872f2087c

Change-Id: Ia09631d8208416107c69bbbf8c4ac4e7f669c4a7
1 file changed