[Mac] Add a feature flag to disable Javascript execution in Applescript

chrome/browser/ui/cocoa/applescript/error_applescript.h

 // Copyright (c) 2010 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.
 
 #ifndef CHROME_BROWSER_UI_COCOA_APPLESCRIPT_ERROR_APPLESCRIPT_H_
 #define CHROME_BROWSER_UI_COCOA_APPLESCRIPT_ERROR_APPLESCRIPT_H_
 
 #import <Cocoa/Cocoa.h>
 
 namespace AppleScript {
@@ skipping 13 matching lines @@
   errInitiatePrinting,
   // Error when invalid tab save type is entered.
   errInvalidSaveType,
   // Error when invalid browser mode is entered.
   errInvalidMode,
   // Error when tab index is out of bounds.
   errInvalidTabIndex,
   // Error when mode is set after browser window is created.
   errSetMode,
   // Error when index of browser window is out of bounds.
-  errWrongIndex
+  errWrongIndex,
+  // Error when JavaScript execution is disabled.
+  errJavaScriptUnsupported
 };
 
 // This function sets an error message to the currently executing command.
 void SetError(ErrorCode errorCode);
 }
 
 #endif  // CHROME_BROWSER_UI_COCOA_APPLESCRIPT_ERROR_APPLESCRIPT_H_