Don't update the save card bubble icon once the browser isn't available.

chrome/browser/ui/autofill/save_card_bubble_controller_impl.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/autofill/save_card_bubble_controller_impl.h"
 
 #include <stddef.h>
 
 #include "chrome/browser/ui/autofill/save_card_bubble_view.h"
 #include "chrome/browser/ui/browser.h"
@@ skipping 281 matching lines @@
   timer_.reset(new base::ElapsedTimer());
 
   AutofillMetrics::LogSaveCardPromptMetric(
       AutofillMetrics::SAVE_CARD_PROMPT_SHOWN, is_uploading_, is_reshow_,
       pref_service_->GetInteger(
           prefs::kAutofillAcceptSaveCreditCardPromptState));
 }
 
 void SaveCardBubbleControllerImpl::UpdateIcon() {
   Browser* browser = chrome::FindBrowserWithWebContents(web_contents());
+  if (!browser)
+    return;
   LocationBar* location_bar = browser->window()->GetLocationBar();
   location_bar->UpdateSaveCreditCardIcon();
 }
 
 void SaveCardBubbleControllerImpl::OpenUrl(const GURL& url) {
   web_contents()->OpenURL(content::OpenURLParams(
       url, content::Referrer(), WindowOpenDisposition::NEW_FOREGROUND_TAB,
       ui::PAGE_TRANSITION_LINK, false));
 }
 
 }  // namespace autofill