Don't show the button for hidden page/browser actions or script badges.

chrome/browser/ui/cocoa/extensions/browser_actions_controller.mm

 // 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.
 
 #import "browser_actions_controller.h"
 
 #include <cmath>
 #include <string>
 
 #include "base/sys_string_conversions.h"
@@ skipping 195 matching lines @@
         if (window != browser_->window()->GetNativeWindow())
           break;
         ExtensionService* service = browser_->profile()->GetExtensionService();
         if (!service)
           break;
         const Extension* extension = service->GetExtensionById(extension_id,
                                                                false);
         if (!extension)
           break;
         BrowserActionButton* button = [owner_ buttonForExtension:extension];
-        [owner_ browserActionClicked:button];
+        // |button| can be NULL when the browser action has its button hidden.
+        if (button)
+          [owner_ browserActionClicked:button];
         break;
       }
       default:
         NOTREACHED() << L"Unexpected notification";
     }
   }
 
   // ExtensionToolbarModel::Observer implementation.
   void BrowserActionAdded(const Extension* extension, int index) {
     [owner_ createActionButtonForExtension:extension withIndex:index];
@@ skipping 633 matching lines @@
   const extensions::ExtensionList& toolbar_items =
       toolbarModel_->toolbar_items();
   if (index < toolbar_items.size()) {
     const Extension* extension = toolbar_items[index];
     return [buttons_ objectForKey:base::SysUTF8ToNSString(extension->id())];
   }
   return nil;
 }
 
 @end