Implement declarative content script API for <webview> [js part].

extensions/renderer/resources/guest_view/web_view.js

 // 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.
 
 // This module implements WebView (<webview>) as a custom element that wraps a
 // BrowserPlugin object element. The object element is hidden within
 // the shadow DOM of the WebView element.
 
 var DocumentNatives = requireNative('document_natives');
 var GuestView = require('guestView').GuestView;
@@ skipping 251 matching lines @@
   $Function.apply(func, null, args);
   return true;
 }
 
 // Implemented when the ChromeWebView API is available.
 WebViewImpl.prototype.maybeGetChromeWebViewEvents = function() {};
 
 // Implemented when the experimental WebView API is available.
 WebViewImpl.maybeGetExperimentalApiMethods = function() { return []; };
 WebViewImpl.prototype.setupExperimentalContextMenus = function() {};
+WebViewImpl.prototype.maybeSetupExperimentalChromeWebViewEvents =
+  function(request) {
+    return request;
+};
 
 GuestViewContainer.registerElement(WebViewImpl);
 
 // Exports.
 exports.WebViewImpl = WebViewImpl;