Revert 66190 - gtk: Add context menu to Bookmark Editor.

BUG=63073
TEST=see bug

Review URL: http://codereview.chromium.org/4973001

TBR=tfarina@chromium.org
Review URL: http://codereview.chromium.org/4953003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@66195 0039d316-1c4b-4281-b951-d872f2087c98