Reland: Remove reference counting from media::VideoDecoder and friends.

In addition:
  * VideoRenderer is now passed a list of decoders via constructor instead of Initialize()
  * WebMediaPlayerImpl's FilterCollection is now built in one shot instead of incrementally

BUG=173313

Review URL: https://chromiumcodereview.appspot.com/14348007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@195212 0039d316-1c4b-4281-b951-d872f2087c98
33 files changed