Mac: Fix SDK 10.11 Compile errors after clang roll in r387792

chrome/browser/ui/cocoa/history_menu_cocoa_controller.mm

Index: chrome/browser/ui/cocoa/history_menu_cocoa_controller.mm
diff --git a/chrome/browser/ui/cocoa/history_menu_cocoa_controller.mm b/chrome/browser/ui/cocoa/history_menu_cocoa_controller.mm
index 7a3d6fac498a4d24d488b55c3f385799dc6dfafc..6d672cbc61da1fd9cad52815826b09fd298d25e2 100644
--- a/chrome/browser/ui/cocoa/history_menu_cocoa_controller.mm
+++ b/chrome/browser/ui/cocoa/history_menu_cocoa_controller.mm
@@ -4,6 +4,7 @@
 
 #import "chrome/browser/ui/cocoa/history_menu_cocoa_controller.h"
 
+#import "base/mac/foundation_util.h"
 #include "chrome/app/chrome_command_ids.h"  // IDC_HISTORY_MENU
 #import "chrome/browser/app_controller_mac.h"
 #include "chrome/browser/profiles/profile.h"
@@ -33,7 +34,8 @@ using content::Referrer;
 }
 
 - (BOOL)validateMenuItem:(NSMenuItem*)menuItem {
-  AppController* controller = [NSApp delegate];
+  AppController* controller =
+      base::mac::ObjCCastStrict<AppController>([NSApp delegate]);
   return ![controller keyWindowIsModal];
 }