[Extensions UI] Check for a browser not being found

chrome/browser/ui/extensions/settings_api_bubble_helpers.cc

 // Copyright (c) 2014 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/extensions/settings_api_bubble_helpers.h"
 
 #include <utility>
 
 #include "build/build_config.h"
 #include "chrome/browser/extensions/ntp_overridden_bubble_delegate.h"
@@ skipping 47 matching lines @@
 void MaybeShowExtensionControlledSearchNotification(
     content::WebContents* web_contents,
     AutocompleteMatch::Type match_type) {
 #if !defined(OS_WIN) && !defined(OS_MACOSX)
   return;
 #endif
 
   if (AutocompleteMatch::IsSearchType(match_type) &&
       match_type != AutocompleteMatchType::SEARCH_OTHER_ENGINE) {
     Browser* browser = chrome::FindBrowserWithWebContents(web_contents);
-    ShowSettingsApiBubble(BUBBLE_TYPE_SEARCH_ENGINE, browser);
+    if (browser)
+      ShowSettingsApiBubble(BUBBLE_TYPE_SEARCH_ENGINE, browser);
   }
 }
 
 void MaybeShowExtensionControlledNewTabPage(
     Browser* browser, content::WebContents* web_contents) {
 #if !defined(OS_WIN)
   return;
 #endif
 
   content::NavigationEntry* entry =
@@ skipping 26 matching lines @@
 
   ntp_overridden_bubble->SetIsActiveBubble();
   ToolbarActionsBar* toolbar_actions_bar =
       browser->window()->GetToolbarActionsBar();
   std::unique_ptr<ToolbarActionsBarBubbleDelegate> bridge(
       new ExtensionMessageBubbleBridge(std::move(ntp_overridden_bubble)));
   toolbar_actions_bar->ShowToolbarActionBubbleAsync(std::move(bridge));
 }
 
 }  // namespace extensions