Prevent crash when trying to dismiss an already dismissed infobar.

chrome/browser/ui/auto_login_info_bar_delegate.cc

Index: chrome/browser/ui/auto_login_info_bar_delegate.cc
diff --git a/chrome/browser/ui/auto_login_info_bar_delegate.cc b/chrome/browser/ui/auto_login_info_bar_delegate.cc
index db5c071a1b632e5e2f1c025115969950a52931fe..b064dc3db61d68478ac5aa8031b01089ecbda088 100644
--- a/chrome/browser/ui/auto_login_info_bar_delegate.cc
+++ b/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);
 }