[Extensions] DCHECK that ExtensionFunctions respond (and only once)

chrome/browser/extensions/api/web_view/chrome_web_view_internal_api.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 CHROME_BROWSER_EXTENSIONS_API_WEB_VIEW_CHROME_WEB_VIEW_INTERNAL_API_H_
 #define CHROME_BROWSER_EXTENSIONS_API_WEB_VIEW_CHROME_WEB_VIEW_INTERNAL_API_H_
 
 #include "base/macros.h"
 #include "extensions/browser/api/guest_view/web_view/web_view_internal_api.h"
 #include "extensions/browser/extension_function.h"
@@ skipping 76 matching lines @@
 class ChromeWebViewInternalShowContextMenuFunction
     : public WebViewInternalExtensionFunction {
  public:
   DECLARE_EXTENSION_FUNCTION("chromeWebViewInternal.showContextMenu",
                              WEBVIEWINTERNAL_SHOWCONTEXTMENU);
 
   ChromeWebViewInternalShowContextMenuFunction();
 
  protected:
   ~ChromeWebViewInternalShowContextMenuFunction() override;
-
- private:
-  // WebViewInternalExtensionFunction implementation.
-  bool RunAsyncSafe(WebViewGuest* guest) override;
+  ResponseAction Run() override;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeWebViewInternalShowContextMenuFunction);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_WEB_VIEW_CHROME_WEB_VIEW_INTERNAL_API_H_