Add DecryptingAudioDecoder.

BUG=123421
TEST=added new tests to media_unittests


Review URL: https://chromiumcodereview.appspot.com/11198017

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@162976 0039d316-1c4b-4281-b951-d872f2087c98
6 files changed