Video Player: Add a cast menu

ui/file_manager/video_player/js/cast/load_cast_extension_api.js

+// Copyright 2014 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.
+
+/**
+ * Defines the cast.ExtensionApi class. This class inherits cast.Api and must
+ * be decraled after the parent is loaded. So we introduce this method to
+ * decrale it with delay.
+ */
+function loadCastExtensionApi() {
+  if (!cast) {
+    console.error('"cast" namespace is not defined.');
+    return;
+  }
+
+  /**
+   * @constructor
+   * @param {string} castExtensionId Extension ID of cast extension.
+   * @extends {cast.Api}
+   */
+  cast.ExtensionApi = function(castExtensionId) {
+    this.castExtensionId_ = castExtensionId;
+    cast.Client.clientId_ = chrome.runtime.id;
+
+    cast.Api.call(this);
+  };
+
+  cast.ExtensionApi.prototype.__proto__ = cast.Api.prototype;
+
+  /**
+   * @override
+   */
+  cast.ExtensionApi.prototype.init = function() {
+    chrome.runtime.onMessageExternal.addListener(
+        this.onMessageExternal_.bind(this));
+    this.sendRequest(cast.AppRequestType.REGISTER_CLIENT, {});
+    cast.isAvailable = true;
+  };
+
+  /**
+   * @override
+   */
+  cast.ExtensionApi.prototype.onDisconnect = function() {};
+
+  /**
+   * @override
+   */
+  cast.ExtensionApi.prototype.sendRequest = function(requestType, request) {
+    if (!this.castExtensionId_)
+      return null;
+
+    var appRequest = new cast.Message(cast.Client.getClientId(),
+        cast.NAME, cast.Client.getNextSeq(), requestType, request);
+
+    // Use response callback for message ACK to detect extension unload.
+    var responseCallback = function() {
+      if (chrome.runtime.lastError) {
+        // Unregister the cast extension.
+        this.castExtensionId_ = '';
+        cast.isAvailable = false;
+        this.onDisconnect();
+      }
+    }.bind(this);
+
+    chrome.runtime.sendMessage(this.castExtensionId_,
+                               appRequest,
+                               responseCallback);
+    return appRequest;
+  };
+
+  /**
+   * @param {string} message
+   * @param {function(boolean)} sender
+   * @param {function(boolean)} sendResponse
+   * @private
+   */
+  cast.ExtensionApi.prototype.onMessageExternal_ = function(message,
+      sender, sendResponse) {
+    if (!this.castExtensionId_ || sender.id != this.castExtensionId_)
+      return;
+
+    // No content.
+    if (!message)
+      return;
+
+    this.processCastMessage(/** @type {cast.Message} */(message));
+  };
+}