Land assets for overview tray button.

R=jonross@chromium.org
TBR=oshima

BUG=349018

Review URL: https://codereview.chromium.org/190723012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256031 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256031
Clean up usage of MediaCodecBridge/MediaDrmBridge::IsAvailable().

- All static methods in MediaCodecBridge and MediaDrmBridge check IsAvailable()
  internally so that callers don't need to check IsAvailable() before calling
  these static methods.
- Remove MediaSourcePlayer::IsTypeSupported() because it's obsolete now.
- Add MediaDrmBridge unittests.

BUG=303864

Review URL: https://codereview.chromium.org/189163003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256032 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256032
Nukes --aura-no-shadows

It's not needed.

BUG=350569
TEST=none
R=ben@chromium.org

Review URL: https://codereview.chromium.org/191663002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256033 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256033