Remove reference counting from media::Pipeline.

BUG=173313
R=acolwell@chromium.org

Review URL: https://codereview.chromium.org/14371023

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@198760 0039d316-1c4b-4281-b951-d872f2087c98
7 files changed