Disable overview mode by default.

BUG=297636
TEST=Without setting any flags, alt+tab and F5 do not engage overview mode.

Review URL: https://codereview.chromium.org/24392004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225406 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225406
Bug fix in  RTP packetizer : Fixing incorrect use of bits/bytes.

Review URL: https://codereview.chromium.org/24395002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225407 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225407