Make ChromeAutofillClient a ZoomObserver.

chrome/browser/ui/zoom/zoom_controller.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/ui/zoom/zoom_controller.h"
 
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser_finder.h"
@@ skipping 238 matching lines @@
 }
 
 void ZoomController::DidNavigateMainFrame(
     const content::LoadCommittedDetails& details,
     const content::FrameNavigateParams& params) {
   // If the main frame's content has changed, the new page may have a different
   // zoom level from the old one.
   UpdateState(std::string());
 }
 
+void ZoomController::WebContentsDestroyed() {
+  // At this point we should no longer be sending any zoom events with this
+  // WebContents.
+  observers_.Clear();
+}
+
 void ZoomController::OnZoomLevelChanged(
     const content::HostZoomMap::ZoomLevelChange& change) {
   UpdateState(change.host);
 }
 
 void ZoomController::UpdateState(const std::string& host) {
   // If |host| is empty, all observers should be updated.
   if (!host.empty()) {
     // Use the navigation entry's URL instead of the WebContents' so virtual
     // URLs work (e.g. chrome://settings). http://crbug.com/153950
@@ skipping 20 matching lines @@
   } else {
     // TODO(wjmaclean) Should we consider having HostZoomMap send both old and
     // new zoom levels here?
     double zoom_level = GetZoomLevel();
     ZoomChangedEventData zoom_change_data(
         web_contents(), zoom_level, zoom_level, zoom_mode_, can_show_bubble);
     FOR_EACH_OBSERVER(
         ZoomObserver, observers_, OnZoomChanged(zoom_change_data));
   }
 }