Add DOM Distiller sync datatype.

This adds a new sync datatype for articles.

BUG=288015

Review URL: https://codereview.chromium.org/24109005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225613 0039d316-1c4b-4281-b951-d872f2087c98
Add experimental AGC to default audio constraints.

TESTED=Experimental AGC was enabled in apprtc.

Review URL: https://codereview.chromium.org/24516002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225614 0039d316-1c4b-4281-b951-d872f2087c98
Add the 200% version of the question mark.

TBR=oshima@chromium.org
BUG=None

Review URL: https://codereview.chromium.org/24906002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225615 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225615