Expose Browser Plugin API in <browser> Tag Shim.

chrome/renderer/resources/extensions/browser_tag.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 <browser> tag via Mutation Observers.
 //
 // The actual tag is implemented via the browser plugin. The internals of this
 // are hidden via Shadow DOM.
 
 var BROWSER_TAG_ATTRIBUTES = ['src', 'width', 'height'];
 
+// All exposed api methods for <browser>, these are forwarded to the browser
+// plugin.
+var BROWSER_TAG_API_METHODS = [
+    'addEventListener',
+    'back',
+    'forward',
+    'getProcessId',
+    'go',
+    'reload',
+    'removeEventListener',
+    'stop',
+    'terminate'
+    ];
+
 window.addEventListener('DOMContentLoaded', function() {
   // Handle <browser> tags already in the document.
   var browserNodes = document.body.querySelectorAll('browser');
   for (var i = 0, browserNode; browserNode = browserNodes[i]; i++) {
     new BrowserTag(browserNode);
   }
 
   // Handle <browser> tags added later.
   var documentObserver = new WebKitMutationObserver(function(mutations) {
     mutations.forEach(function(mutation) {
       for (var i = 0, addedNode; addedNode = mutation.addedNodes[i]; i++) {
         if (addedNode.tagName == 'BROWSER') {
           new BrowserTag(addedNode);
         }
       }
     });
   });
   documentObserver.observe(document, {subtree: true, childList: true});
 });
 
 /**
  * @constructor
  */
 function BrowserTag(node) {
   this.node_ = node;
   var shadowRoot = new WebKitShadowRoot(node);
 
   this.objectNode_ = document.createElement('object');
   this.objectNode_.type = 'application/browser-plugin';
+  var objectNode = this.objectNode_;

[Mihai Parparita -not on Chrome, 2012/10/13 00:13:53]

This is no longer needed.

[lazyboy, 2012/10/13 02:44:08]

Removed.

   BROWSER_TAG_ATTRIBUTES.forEach(this.copyAttribute_, this);
+
   shadowRoot.appendChild(this.objectNode_);
 
+  // this.objectNode_[apiMethod] are defined after the shadow object is appended
+  // to the shadow root.
+  BROWSER_TAG_API_METHODS.forEach(function(apiMethod) {
+    node[apiMethod] = this.objectNode_[apiMethod].bind(this.objectNode_);
+  }, this);
+
   // Map attribute modifications on the <browser> tag to changes on the
   // underlying <object> node.
   var handleMutation = this.handleMutation_.bind(this);
   var observer = new WebKitMutationObserver(function(mutations) {
     mutations.forEach(handleMutation);
   });
   observer.observe(
       this.node_,
       {attributes: true, attributeFilter: BROWSER_TAG_ATTRIBUTES});
 
@@ skipping 31 matching lines @@
   }
 };
 
 /**
  * @private
  */
 BrowserTag.prototype.copyAttribute_ = function(attributeName) {
   this.objectNode_.setAttribute(
       attributeName, this.node_.getAttribute(attributeName));
 };