Prevent crash when trying to dismiss an already dismissed infobar.

 The owner of an infobar delegate might be NULL if the infobar is
already in the process of being deleted. Checking for this before asking
it to dismiss in the auto-login infobar.

TEST=None
BUG=None


Review URL: https://chromiumcodereview.appspot.com/10701080

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@145896 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/ui/auto_login_info_bar_delegate.cc

@@ -222,5 +222,8 @@ void AutoLoginInfoBarDelegate::Observe(int type,
                                        const NotificationSource& source,
                                        const NotificationDetails& details) {
   DCHECK_EQ(chrome::NOTIFICATION_GOOGLE_SIGNED_OUT, type);
-  owner()->RemoveInfoBar(this);
+  // owner() can be NULL when InfoBarTabHelper removes us. See
+  // |InfoBarDelegate::clear_owner|.
+  if (owner())
+    owner()->RemoveInfoBar(this);
 }