<webview>: BrowserPlugin methods are not defined immediately after the shadow object is appended to…

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 watchForTag = require("tagWatcher").watchForTag;
@@ skipping 40 matching lines @@
   // The <object> node fills in the <browser> container.
   this.objectNode_.style.width = '100%';
   this.objectNode_.style.height = '100%';
   WEB_VIEW_ATTRIBUTES.forEach(function(attributeName) {
     this.objectNode_.setAttribute(
         attributeName, this.node_.getAttribute(attributeName));
   }, this);
 
   shadowRoot.appendChild(this.objectNode_);
 
-  // this.objectNode_[apiMethod] are defined after the shadow object is appended
-  // to the shadow root.
+  // this.objectNode_[apiMethod] are not necessarily defined immediately after
+  // the shadow object is appended to the shadow root.

[sadrul, 2013/01/09 18:51:24]

Interesting. Is this because of a race, or is that always the case (i.e. the
methods not being available at this point)?

[Fady Samuel, 2013/01/09 19:18:42]

It works some of the time, so this is a race. This code is generally more robust
because it avoids accessing the innards of objectNode_ until the call is
actually made.

   WEB_VIEW_API_METHODS.forEach(function(apiMethod) {
-    node[apiMethod] = this.objectNode_[apiMethod].bind(this.objectNode_);
+    var self = this;

[arv (Not doing code reviews), 2013/01/09 19:40:01]

Move self out of inner function?

var self = this;
WEB_VIEW_API_METHODS.forEach(function(apiMethod) {
  node[apiMethod] = function(var_args) {
    return self.objectNode_[apiMethod].apply(self.objectNode_, arguments);
  };
});

[Fady Samuel, 2013/01/09 19:49:25]

Done.

+    node[apiMethod] = function(var_args) {
+      return self.objectNode_[apiMethod].apply(self.objectNode_, arguments);
+    };
   }, this);
 
   // Map attribute modifications on the <webview> tag to property changes in
   // the underlying <object> node.
   var handleMutation = this.handleMutation_.bind(this);
   var observer = new WebKitMutationObserver(function(mutations) {
     mutations.forEach(handleMutation);
   });
   observer.observe(
       this.node_,
@@ skipping 75 matching lines @@
   var node = this.node_;
   this.objectNode_.addEventListener('-internal-' + eventname, function(e) {
     var evt = new Event(eventname);
     var detail = e.detail ? JSON.parse(e.detail) : {};
     attribs.forEach(function(attribName) {
       evt[attribName] = detail[attribName];
     });
     node.dispatchEvent(evt);
   });
 }