[PPAPI][MediaStream] Add browser tests for MediaStreamVideoTrack

BUG=330851

Review URL: https://codereview.chromium.org/171233014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253466 0039d316-1c4b-4281-b951-d872f2087c98
[PPAPI][MediaStream] Add unit tests for code in ppapi/shared_impl/

BUG=330851

Review URL: https://codereview.chromium.org/172943003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253467 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253466
Avoids starting volume-change observer until we enter Communication mode.

BUG=none
TEST=manual tests of different WebRTC demos
R=bulach@chromium.org, tommi@chromium.org

Review URL: https://codereview.chromium.org/177093004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253468 0039d316-1c4b-4281-b951-d872f2087c98
Remove p2p socket API from content/public

We're not using p2p socket any more in content renderer public. Remove the APIs.

BUG=344624

Review URL: https://codereview.chromium.org/173203002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253469 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253469