[Mac] Inform reference counted objects that hold a weak Browser* when the Browser is being destroye…

chrome/browser/ui/cocoa/wrench_menu/wrench_menu_controller.mm

 // Copyright (c) 2011 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.
 
 #import "chrome/browser/ui/cocoa/wrench_menu/wrench_menu_controller.h"
 
 #include "base/basictypes.h"
 #include "base/mac/bundle_locations.h"
 #include "base/strings/string16.h"
 #include "base/strings/sys_string_conversions.h"
@@ skipping 96 matching lines @@
     observer_.reset(new WrenchMenuControllerInternal::ZoomLevelObserver(
         self,
         ui_zoom::ZoomEventManager::GetForBrowserContext(browser->profile())));
     acceleratorDelegate_.reset(
         new WrenchMenuControllerInternal::AcceleratorDelegate());
     [self createModel];
   }
   return self;
 }
 
+- (void)browserWillBeDestroyed {
+  // This method indicates imminent destruction. Destroy owned objects that hold
+  // a weak Browser*, or pass this call onto reference counted objects.
+  recentTabsMenuModelDelegate_.reset();
+  wrenchMenuModel_.reset();
+  [self setModel:nullptr];
+  buttonViewController_.reset();
+
+  [browserActionsController_ browserWillBeDestroyed];
+
+  browser_ = nullptr;
+}
+
 - (void)addItemToMenu:(NSMenu*)menu
               atIndex:(NSInteger)index
             fromModel:(ui::MenuModel*)model {
   // Non-button item types should be built as normal items, with the exception
   // of the extensions overflow menu.
   int command_id = model->GetCommandIdAt(index);
   if (model->GetTypeAt(index) != ui::MenuModel::TYPE_BUTTON_ITEM &&
       command_id != IDC_EXTENSIONS_OVERFLOW_MENU) {
     [super addItemToMenu:menu
                  atIndex:index
@@ skipping 194 matching lines @@
     recentTabsMenuModelDelegate_.reset(
         new RecentTabsMenuModelDelegate(model, [self recentTabsSubmenu]));
   }
 }
 
 - (BrowserActionsController*)browserActionsController {
   return browserActionsController_.get();
 }
 
 - (void)createModel {
+  DCHECK(browser_);
   recentTabsMenuModelDelegate_.reset();
   wrenchMenuModel_.reset(
       new WrenchMenuModel(acceleratorDelegate_.get(), browser_));
   [self setModel:wrenchMenuModel_.get()];
 
   buttonViewController_.reset(
       [[WrenchMenuButtonViewController alloc] initWithController:self]);
   [buttonViewController_ view];
 }
 
@@ skipping 121 matching lines @@
     controller_ = controller;
   }
   return self;
 }
 
 - (IBAction)dispatchWrenchMenuCommand:(id)sender {
   [controller_ dispatchWrenchMenuCommand:sender];
 }
 
 @end  // @implementation WrenchMenuButtonViewController