Added |-cancelJavaScriptDialogsForWebController:| to UI delegate.

ios/web/public/web_state/crw_web_user_interface_delegate.h

 // Copyright 2014 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 IOS_WEB_PUBLIC_WEB_STATE_CRW_WEB_USER_INTERFACE_DELEGATE_H_
 #define IOS_WEB_PUBLIC_WEB_STATE_CRW_WEB_USER_INTERFACE_DELEGATE_H_
 
 #include <Foundation/Foundation.h>
 
 @class CRWWebController;
@@ skipping 31 matching lines @@
 // text.  If the cancel but is pressed, |input| will be nil.  If this selector
 // isn't implemented, the completion handler provided by the web view will be
 // called with |input| = nil.
 - (void)webController:(CRWWebController*)webController
     runJavaScriptTextInputPanelWithPrompt:(NSString*)message
                               defaultText:(NSString*)defaultText
                                requestURL:(const GURL&)requestURL
                         completionHandler:
                             (void (^)(NSString* input))completionHandler;
 
+// Cancels any outstanding JavaScript dialogs requested by the functions above.
+- (void)cancelJavaScriptDialogsForWebController:
+    (CRWWebController*)webController;
+
 // Displays a context menu for DOM element. |point| and |view| represent the
 // location and UIView where the context menu was triggered by a user gesture.
 // |menuInfo| keys are defined in crw_context_menu_provider.h.
 // TODO(eugenebut): create DOMElement class (tag + attributes) and pass
 // it and referrer as separate arguments instead of |menuInfo|.
 - (void)webController:(CRWWebController*)webController
        runContextMenu:(NSDictionary*)menuInfo
               atPoint:(CGPoint)point
                inView:(UIView*)view;
 
 @end
 
 #endif  // IOS_WEB_PUBLIC_WEB_STATE_CRW_WEB_USER_INTERFACE_DELEGATE_H_