Renaming remaining WebRTC browser tests.

Will require https://codereview.chromium.org/137793008 to land shortly
after this landing to avoid missing to run tests.

R=tommi@chromium.org
NOTRY=True

Review URL: https://codereview.chromium.org/137753004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245523 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245523
Split WebRTC browser tests in getusermedia and peerconnection tests.

The content browsertests file for WebRTC was growing a bit large. I
extracted the getUserMedia-focused tests into a test of its own and
left the peerconnection tests.

Also renamed all WebRTC content browsertests to use the WebRtc naming
convention, which seems to be the most common in the production code.

Note: this patch will require some filter renames on the WebRTC bots.

R=tommi@chromium.org

Review URL: https://codereview.chromium.org/131203005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245524 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245524