Streamlined sideload UI for extensions from the webstore.

http://i.imgur.com/OOjPmDJ.png

Sideloaded extensions that have a webstore update URL have a global error bubble replacing the normal extension install dialog.

Still TODO:
- Making this not appear for new profiles.
- Unit tests.

BUG=229083

Review URL: https://chromiumcodereview.appspot.com/14328029

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@195391 0039d316-1c4b-4281-b951-d872f2087c98
3 files changed