GTK: hook up drag and drop of browser actions (for reordering).

The changes are propagated across open chrome windows, but are not persisted between sessions yet.

BUG=26990

Review URL: http://codereview.chromium.org/463056

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@34272 0039d316-1c4b-4281-b951-d872f2087c98
10 files changed