Ensure URL is updated after a cross-site navigation is pre-empted by

      an &quotignored&quot navigation.

BUG=77507
TEST=NavigationControllerTest.LoadURL_IgnorePreemptsPending

Review URL: http://codereview.chromium.org/6826015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@81307 0039d316-1c4b-4281-b951-d872f2087c98