Split web_view_internal_api and move part of it to extensions.

chrome/renderer/resources/extensions/chrome_web_view_internal_custom_bindings.js

 // 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.
 
 // Custom binding for <webview> contextMenus API.
 // Note that this file mimics custom bindings for chrome.contextMenus API
 // which resides in context_menus_custom_bindings.js. The functions in this file
 // have an extra instanceId parameter in the beginning, which corresponds to the
 // id of the <webview>.
 //
 // TODO(lazyboy): Share common code /w context_menus_custom_bindings.js.
 
 var EventBindings = require('event_bindings');
-var binding = require('binding').Binding.create('webViewInternal');
+var binding = require('binding').Binding.create('chromeWebViewInternal');
 var contextMenuNatives = requireNative('context_menus');
 var sendRequest = require('sendRequest').sendRequest;
 
 binding.registerCustomHook(function(bindingsAPI) {
   var apiFunctions = bindingsAPI.apiFunctions;
 
   var webviewContextMenus = {};
   webviewContextMenus.generatedIdHandlers = {};
   webviewContextMenus.stringIdHandlers = {};
 
@@ skipping 95 matching lines @@
     if (chrome.runtime.lastError) {
       return;
     }
     var instanceId = request.args[0];
     webviewContextMenus.stringIdHandlers[instanceId] = {};
     webviewContextMenus.generatedIdHandlers[instanceId] = {};
   });
 
 });
 
-exports.WebView = binding.generate();
+exports.ChromeWebView = binding.generate();