Catch more exceptions in MediaCodecBridge.

Exceptions could be thrown in start() and/or getOutputBuffers() when we open too many MediaCodec objects and exceed the capacity of a mobile device.

BUG=303419,304956
TEST=This prevents crash in tests that create multiple <video> tags. These tests will still fail due to device limitation.

Review URL: https://codereview.chromium.org/26880004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228052 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 228052