Add credential passing API for Chrome OS SAML login

chrome/browser/resources/gaia_auth/background.js

 // Copyright 2013 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.
 
 /**
  * @fileoverview
- * The background script of auth extension that bridges the communications
- * between main and injected script.
- * Here are the communications along a SAML sign-in flow:
- * 1. Main script sends an 'onAuthStarted' signal to indicate the authentication
- *    flow is started and SAML pages might be loaded from now on;
- * 2. After the 'onAuthTstarted' signal, injected script starts to scraping
- *    all password fields on normal page (i.e. http or https) and sends page
- *    load signal as well as the passwords to the background script here;
+ * A background script of the auth extension that bridges the communication
+ * between the main and injected scripts.
+ *
+ * Here is an overview of the communication flow when SAML is being used:
+ * 1. The main script sends the |startAuth| signal to this background script,
+ *    indicating that the authentication flow has started and SAML pages may be
+ *    loaded from now on.
+ * 2. A script is injected into each SAML page. The injected script sends three
+ *    main types of messages to this background script:
+ *    a) A |pageLoaded| message is sent when the page has been loaded. This is
+ *       forwarded to the main script as |onAuthPageLoaded|.
+ *    b) If the SAML provider supports the credential passing API, the API calls
+ *       are sent to this backgroudn script as |apiCall| messages. These
+ *       messages are forwarded unmodified to the main script.
+ *    c) The injected script scrapes passwords. They are sent to this background
+ *       script in |updatePassword| messages. The main script can request a list
+ *       of the scraped passwords by sending the |getScrapedPasswords| message.
  */
 
 /**
- * BackgroundBridge holds the main script's state and the scraped passwords
- * from the injected script to help the two collaborate.
+ * BackgroundBridge allows the main script and the injected script to
+ * collaborate. It forwards credentials API calls to the main script and
+ * maintains a list of scraped passwords.
  */
 function BackgroundBridge() {
 }
 
 BackgroundBridge.prototype = {
   // Gaia URL base that is set from main auth script.
   gaiaUrl_: null,
 
   // Whether auth flow has started. It is used as a signal of whether the
   // injected script should scrape passwords.
@@ skipping 52 matching lines @@
         this.onGetScrapedPasswords_.bind(this));
   },
 
   /**
    * Sets up the communication channel with the injected script.
    */
   setupForInjected_: function(port) {
     this.channelInjected_ = new Channel();
     this.channelInjected_.init(port);
     this.channelInjected_.registerMessage(
+        'apiCall', this.onAPICall_.bind(this));
+    this.channelInjected_.registerMessage(
         'updatePassword', this.onUpdatePassword_.bind(this));
     this.channelInjected_.registerMessage(
         'pageLoaded', this.onPageLoaded_.bind(this));
   },
 
   /**
    * Handler for 'setGaiaUrl' signal sent from the main script.
    */
   onSetGaiaUrl_: function(msg) {
     this.gaiaUrl_ = msg.gaiaUrl;
@@ skipping 32 matching lines @@
    * @return {Array.<string>} The array with de-duped scraped passwords.
    */
   onGetScrapedPasswords_: function() {
     var passwords = {};
     for (var property in this.passwordStore_) {
       passwords[this.passwordStore_[property]] = true;
     }
     return Object.keys(passwords);
   },
 
+  onAPICall_: function(msg) {
+    this.channelMain_.send(msg);
+  },
+
   onUpdatePassword_: function(msg) {
     if (!this.authStarted_)
       return;
 
     this.passwordStore_[msg.id] = msg.password;
   },
 
   onPageLoaded_: function(msg) {
     this.channelMain_.send({name: 'onAuthPageLoaded', url: msg.url});
   }
 };
 
 var backgroundBridge = new BackgroundBridge();
 backgroundBridge.run();