Revert 135525 - Add a first-class off-store install UI to chrome://extensions/.

This patch implements GTK only. Other ports will be separate CLs.

BUG=55584

Review URL: https://chromiumcodereview.appspot.com/10270031

TBR=aa@chromium.org
Review URL: https://chromiumcodereview.appspot.com/10382025

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@135528 0039d316-1c4b-4281-b951-d872f2087c98
14 files changed