Expose Browser Plugin API in <browser> Tag Shim.

chrome/test/data/extensions/platform_apps/browser_tag/main.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.
 
 onload = function() {
   chrome.test.runTests([
     function browserTag() {
       var browserTag = document.querySelector('browser');
       // Since we can't currently inspect the page loaded inside the <browser>,
       // the only way we can check that the shim is working is by changing the
@@ skipping 30 matching lines @@
           document.body.appendChild(dynamicBrowserTag);
 
           setTimeout(function() {
             chrome.test.assertEq(330, dynamicBrowserTag.offsetWidth);
             chrome.test.assertEq(230, dynamicBrowserTag.offsetHeight);
 
             chrome.test.succeed();
           }, 0);
         }, 0);
       }, 0);
+    },
+
+    function browserTagApiMethodExistence() {
+      var browserTag = document.createElement('browser');
+      browserTag.setAttribute('src', 'data:text/html,browser tag check api');
+      var apiMethodsToCheck = [
+        'addEventListener',
+        'back',
+        'forward',
+        'getProcessId',
+        'go',
+        'reload',
+        'removeEventListener',
+        'stop',
+        'terminate'
+      ];
+      document.body.appendChild(browserTag);
+
+      // Timeout is necessary to give the mutation observers a chance to fire.
+      setTimeout(function() {
+        for (var i = 0; i < apiMethodsToCheck.length; ++i) {
+          chrome.test.assertEq('function',
+                               typeof browserTag[apiMethodsToCheck[i]]);
+        }
+        chrome.test.succeed();
+      }, 0);
     }
   ]);
 };