remove SK_SUPPORT_LEGACY_PIXELREF_CONSTRUCTOR now that call-sites have been updated

BUG=

Review URL: https://codereview.chromium.org/123233002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242819 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242819
Sends getUserMedia request info to webrtc-internals.
WebRTCInternals caches the info to send to internal pages opened in the future.
The UI for representing the info on the internal page will be added later.

BUG=304023

Review URL: https://codereview.chromium.org/61733017

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242820 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242820