Delete unneeded pending entries in DidFailProvisionalLoad to prevent a spoof.

BUG=280512
BUG=278899
TEST=See bug for repro steps.

Review URL: https://chromiumcodereview.appspot.com/23978003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@222146 0039d316-1c4b-4281-b951-d872f2087c98
void NavigationControllerImpl::GoToOffset(int offset) {
  if (!CanGoToOffset(offset))
    return;

  GoToIndex(GetIndexForOffset(offset));
}

void NavigationControllerImpl::GoToOffset(int offset) {
  if (!CanGoToOffset(offset))
    return;

  GoToIndex(GetIndexForOffset(offset));
}
