Fix unsafe attempt to blindly access owner() in GoogleURLTracker::Close().

chrome/browser/google/google_url_tracker.cc

 // Copyright (c) 2012 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/google/google_url_tracker.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 85 matching lines @@
   DCHECK_EQ(GetHost(new_google_url_), GetHost(new_google_url));
   new_google_url_ = new_google_url;
 }
 
 void GoogleURLTrackerInfoBarDelegate::Show() {
   showing_ = true;
   owner()->AddInfoBar(this);  // May delete |this| on failure!
 }
 
 void GoogleURLTrackerInfoBarDelegate::Close(bool redo_search) {
-  if (redo_search) {
+  if (redo_search && owner()) {
     // Re-do the user's search on the new domain.
     url_canon::Replacements<char> replacements;
     const std::string& host(new_google_url_.host());
     replacements.SetHost(host.data(), url_parse::Component(0, host.length()));
     GURL new_search_url(search_url_.ReplaceComponents(replacements));
     if (new_search_url.is_valid()) {
       content::OpenURLParams params(new_search_url, content::Referrer(),
           CURRENT_TAB, content::PAGE_TRANSITION_GENERATED, false);
       owner()->web_contents()->OpenURL(params);
     }
@@ skipping 394 matching lines @@
 
 void GoogleURLTracker::CloseAllInfoBars(bool redo_searches) {
   // Close all infobars, whether they've been added to tabs or not.
   while (!infobar_map_.empty())
     infobar_map_.begin()->second->Close(redo_searches);
 
   // Any registered listeners for NAV_ENTRY_COMMITTED and TAB_CLOSED are now
   // irrelevant as the associated infobars are gone.
   registrar_.RemoveAll();
 }