<webview>: Allocate the view instance ID from the WebView shim

chrome/renderer/resources/extensions/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.
 
 // Shim that simulates a <webview> tag via Mutation Observers.
 //
 // The actual tag is implemented via the browser plugin. The internals of this
 // are hidden via Shadow DOM.
 
 var addTagWatcher = require('tagWatcher').addTagWatcher;
 var eventBindings = require('event_bindings');
 
 /** @type {Array.<string>} */
 var WEB_VIEW_ATTRIBUTES = ['name', 'src', 'partition', 'autosize', 'minheight',
     'minwidth', 'maxheight', 'maxwidth'];
 
 var WEB_VIEW_EVENTS = {
   'sizechanged': ['oldHeight', 'oldWidth', 'newHeight', 'newWidth'],
 };
 
+var webViewInstanceIdCounter = 0;
+
 var createEvent = function(name) {
   var eventOpts = {supportsListeners: true, supportsFilters: true};
   return new eventBindings.Event(name, undefined, eventOpts);
 };
 
 var WEB_VIEW_EXT_EVENTS = {
   'close': {
     evt: createEvent('webview.onClose'),
     fields: []
   },
@@ skipping 305 matching lines @@
       this.webviewNode_.setAttribute(mutation.attributeName, newValue);
     }
   }
 };
 
 /**
  * @private
  */
 WebView.prototype.setupWebviewNodeEvents_ = function() {
   var self = this;
+  this.viewInstanceId_ = ++webViewInstanceIdCounter;
   var onInstanceIdAllocated = function(e) {
     var detail = e.detail ? JSON.parse(e.detail) : {};
     self.instanceId_ = detail.windowId;
     var params = {
-      'api': 'webview'
+      'api': 'webview',
+      'instanceId': self.viewInstanceId_
     };
     self.browserPluginNode_['-internal-attach'](params);
 
     for (var eventName in WEB_VIEW_EXT_EVENTS) {
       self.setupExtEvent_(eventName, WEB_VIEW_EXT_EVENTS[eventName]);
     }
   };
   this.browserPluginNode_.addEventListener('-internal-instanceid-allocated',
                                            onInstanceIdAllocated);
 
@@ skipping 276 matching lines @@
   });
 };
 
 /**
  * Implemented when the experimental API is available.
  * @private
  */
 WebView.prototype.maybeSetupExperimentalAPI_ = function() {};
 
 exports.WebView = WebView;