[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

Index: chrome/browser/ui/cocoa/wrench_menu/wrench_menu_controller.mm
diff --git a/chrome/browser/ui/cocoa/wrench_menu/wrench_menu_controller.mm b/chrome/browser/ui/cocoa/wrench_menu/wrench_menu_controller.mm
index 0a200cacc02a0785e4c1c050eb07e67fbb95d620..0bfe5f98c32895ec61f147f76fe7cb871a75045b 100644
--- a/chrome/browser/ui/cocoa/wrench_menu/wrench_menu_controller.mm
+++ b/chrome/browser/ui/cocoa/wrench_menu/wrench_menu_controller.mm
@@ -114,6 +114,19 @@ class ZoomLevelObserver {
   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();
+  [self setModel:nullptr];
+  wrenchMenuModel_.reset();
+  buttonViewController_.reset();
+
+  [browserActionsController_ browserWillBeDestroyed];
+
+  browser_ = nullptr;
+}
+
 - (void)addItemToMenu:(NSMenu*)menu
               atIndex:(NSInteger)index
             fromModel:(ui::MenuModel*)model {
@@ -328,6 +341,7 @@ class ZoomLevelObserver {
 }
 
 - (void)createModel {
+  DCHECK(browser_);
   recentTabsMenuModelDelegate_.reset();
   wrenchMenuModel_.reset(
       new WrenchMenuModel(acceleratorDelegate_.get(), browser_));