Make sure that the PermissionBubbleView's delegate is set before it is shown.

BUG=None

Review URL: https://codereview.chromium.org/151853002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249533 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 249533