Use HTML messages to inform GAIA about deviceId.

chrome/browser/resources/gaia_auth_host/authenticator.js

Index: chrome/browser/resources/gaia_auth_host/authenticator.js
diff --git a/chrome/browser/resources/gaia_auth_host/authenticator.js b/chrome/browser/resources/gaia_auth_host/authenticator.js
index 0fc093e2689b64f806cb411210bdace2771b41e8..3dea8adf47859439279388fedd4513ae553a65d1 100644
--- a/chrome/browser/resources/gaia_auth_host/authenticator.js
+++ b/chrome/browser/resources/gaia_auth_host/authenticator.js
@@ -424,29 +424,40 @@ cr.define('cr.login', function() {
   };
 
   /**
-   * Invoked when an HTML5 message is received from the webview element.
+   * Returns true if given HTML5 message is received from the webview element.
    * @param {object} e Payload of the received HTML5 message.
-   * @private
    */
-  Authenticator.prototype.onMessageFromWebview_ = function(e) {
+  Authenticator.prototype.isGaiaMessage = function(e) {
     if (!this.isWebviewEvent_(e))
-      return;
+      return false;
 
     // The event origin does not have a trailing slash.
     if (e.origin != this.idpOrigin_.substring(0, this.idpOrigin_.length - 1)) {
-      return;
+      return false;
     }
 
     // Gaia messages must be an object with 'method' property.
     if (typeof e.data != 'object' || !e.data.hasOwnProperty('method')) {
-      return;
+      return false;
     }
+    return true;
+  };
+
+  /**
+   * Invoked when an HTML5 message is received from the webview element.
+   * @param {object} e Payload of the received HTML5 message.
+   * @private
+   */
+  Authenticator.prototype.onMessageFromWebview_ = function(e) {
+    if (!this.isGaiaMessage(e))
+      return;
 
     var msg = e.data;
     if (msg.method == 'attemptLogin') {
       this.email_ = msg.email;
       this.password_ = msg.password;
       this.chooseWhatToSync_ = msg.chooseWhatToSync;
+      this.dispatchEvent(new CustomEvent('attemptLogin', {detail: msg.email}));

[Nikita (slow), 2015/04/22 16:51:52]

As discussed, we should only process 'attemptLogin' in such way when it only
contains email. No need to process further 'attemptLogin' messages (email +
password).

[Alexander Alekseev, 2015/04/22 17:58:07]

Done.

     } else if (msg.method == 'dialogShown') {
       this.dispatchEvent(new Event('dialogShown'));
     } else if (msg.method == 'dialogHidden') {
@@ -665,6 +676,19 @@ cr.define('cr.login', function() {
   };
 
   /**
+   * Informs Gaia of new deviceId to be used.
+   */
+  Authenticator.prototype.updateDeviceId = function(deviceId) {
+    var msg = {
+      'method': 'updateDeviceId',
+      'deviceId': deviceId,
+    };
+
+    var currentUrl = this.webview_.src;
+    this.webview_.contentWindow.postMessage(msg, currentUrl);
+  };
+
+  /**
    * The current auth flow of the hosted auth page.
    * @type {AuthFlow}
    */