Add the SmartClip feature.

This patch is based on https://codereview.chromium.org/103913013/ by Juhui Lee <juhui24.lee@samsung.com>.

BUG=329809
R=jschuh@chromium.org

Review URL: https://codereview.chromium.org/98793006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242641 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242641