Implementation of chrome://cast page.

chrome/browser/resources/cast/cast.js

+// Copyright 2016 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.
+
+window.addEventListener('load', function init() {
+  var ev = document.querySelector('extensionview');
+
+  /**
+   * @param {string} str
+   * @return {!Array<string>}
+   */
+  var splitUrlOnHash = function(str) {
+    str = str || '';
+    var pos = str.indexOf('#');
+    return (pos !== -1) ? [str.substr(0, pos), str.substr(pos + 1)] : [str, ''];
+  };
+
+  new MutationObserver(function() {
+    var newHash = splitUrlOnHash(ev.getAttribute('src'))[1];
+    var oldHash = window.location.hash.substr(1);
+    if (newHash !== oldHash) {
+      window.location.hash = newHash;
+    }
+  }).observe(ev, {
+    attributes: true
+  });
+
+  window.addEventListener('hashchange', function() {
+    var newHash = window.location.hash.substr(1);
+    var evSrcParts = splitUrlOnHash(ev.getAttribute('src'));
+    if (newHash !== evSrcParts[1]) {
+      ev.load(evSrcParts[0] + '#' + newHash);
+    }
+  });
+
+  ev.load('chrome-extension://enhhojjnijigcajfphajepfemndkmdlo' +

[apacible, 2016/05/16 19:04:07]

If this fails to load, do we expect the default "Page cannot be displayed"
error?

[apacible, 2016/05/16 19:04:07]

For different channels, the extension ID will be different. We keep track of it
here:
https://code.google.com/p/chromium/codesearch#chromium/src/chrome/browser/med...

[sheretov, 2016/05/17 01:59:26]

We expect to get the default behavior when extensionView fails to load a URL,
which right now results in a promise rejection error message in the JS console,
while the page remains blank.  This shouldn't happen unless something is
seriously broken, however.

[sheretov, 2016/05/17 01:59:26]

Done, but I'm not sure if this is the right mechanism in light of
crbug.com/597778.

[apacible, 2016/05/18 17:30:42]

mfoltz: thoughts?

[apacible, 2016/05/18 17:30:42]

If the extensionview fails to load the URL, could we remove/hide the
extensionview element and show an error message? It likely won't happen unless
the 1) component extension wasn't installed 2) there are other issues, so I'm
fine with this being added later.

[sheretov, 2016/05/18 18:11:11]

Sounds good.  I'll put this in a subsequent CL.

+          '/cast_setup/devices.html');
+});
+