[cros] Change how we track momemt to emit login-prompt-visible signal.

chrome/browser/resources/chromeos/login/screen_gaia_signin.js

Index: chrome/browser/resources/chromeos/login/screen_gaia_signin.js
diff --git a/chrome/browser/resources/chromeos/login/screen_gaia_signin.js b/chrome/browser/resources/chromeos/login/screen_gaia_signin.js
index 7fdf7438242310263c8f041db3164947a873b795..534c0bc234d6ca7ac12bf00660faa489b42537cb 100644
--- a/chrome/browser/resources/chromeos/login/screen_gaia_signin.js
+++ b/chrome/browser/resources/chromeos/login/screen_gaia_signin.js
@@ -8,10 +8,10 @@
 
 cr.define('login', function() {
   // Gaia loading time after which portal check should be fired.
-  const GAIA_LOADING_PORTAL_SUSSPECT_TIME_SEC = 5;
+  /** @const */ var GAIA_LOADING_PORTAL_SUSSPECT_TIME_SEC = 5;
 
   // Maximum Gaia loading time in seconds.
-  const MAX_GAIA_LOADING_TIME_SEC = 60;
+  /** @const */ var MAX_GAIA_LOADING_TIME_SEC = 60;
 
   /**
    * Creates a new sign in screen div.
@@ -59,7 +59,7 @@ cr.define('login', function() {
 
     // Email of the user, which is logging in using offline mode.
     // @type {string}
-    email: "",
+    email: '',
 
     // Timer id of pending load.
     loadingTimer_: undefined,
@@ -103,8 +103,8 @@ cr.define('login', function() {
       chrome.send('fixCaptivePortal');
       this.loadingTimer_ = window.setTimeout(
           this.onLoadingTimeOut_.bind(this),
-          (MAX_GAIA_LOADING_TIME_SEC - GAIA_LOADING_PORTAL_SUSSPECT_TIME_SEC)
-              * 1000);
+          (MAX_GAIA_LOADING_TIME_SEC - GAIA_LOADING_PORTAL_SUSSPECT_TIME_SEC) *
+          1000);
     },
 
     /**
@@ -155,8 +155,8 @@ cr.define('login', function() {
 
     /**
      * Event handler that is invoked just before the frame is shown.
-     * @param data {string} Screen init payload. Url of auth extension start
-     *        page.
+     * @param {string} data Screen init payload. Url of auth extension start
+     *                      page.
      */
     onBeforeShow: function(data) {
       // Announce the name of the screen, if accessibility is on.
@@ -176,7 +176,7 @@ cr.define('login', function() {
     loadAuthExtension_: function(data) {
       this.silentLoad_ = data.silentLoad;
       this.isLocal = data.isLocal;
-      this.email = "";
+      this.email = '';
 
       // Offline sign-in is only allowed for the case when users aren't shown
       // because there is no other way for an user to enter when device is
@@ -252,7 +252,7 @@ cr.define('login', function() {
 
     /**
      * Checks if message comes from the loaded authentication extension.
-     * @param e {object} Payload of the received HTML5 message.
+     * @param {object} e Payload of the received HTML5 message.
      * @type {boolean}
      */
     isAuthExtMessage_: function(e) {
@@ -263,7 +263,7 @@ cr.define('login', function() {
 
     /**
      * Event handler that is invoked when HTML5 message is received.
-     * @param e {object} Payload of the received HTML5 message.
+     * @param {object} e Payload of the received HTML5 message.
      */
     onMessage_: function(e) {
       if (!this.isAuthExtMessage_(e)) {
@@ -276,7 +276,7 @@ cr.define('login', function() {
       console.log('GaiaSigninScreen.onMessage_: method=' + msg.method);
 
       if (msg.method == 'completeLogin') {
-        chrome.send('completeLogin', [msg.email, msg.password] );
+        chrome.send('completeLogin', [msg.email, msg.password]);
         this.loading = true;
         // Now that we're in logged in state header should be hidden.
         Oobe.getInstance().headerHidden = true;
@@ -291,7 +291,11 @@ cr.define('login', function() {
         }
         this.clearRetry_();
         chrome.send('loginWebuiReady');
-      } else if (msg.method =='offlineLogin') {
+        // Report back sign in UI being painted.
+        window.webkitRequestAnimationFrame(function() {
+          chrome.send('loginVisible');
+        });
+      } else if (msg.method == 'offlineLogin') {
         this.email = msg.email;
         chrome.send('authenticateUser', [msg.email, msg.password]);
         this.loading = true;
@@ -353,8 +357,8 @@ cr.define('login', function() {
       if (this.retryCount_ >= 3 || this.retryTimer_)
         return;
 
-      const MAX_DELAY = 7200;  // 7200 seconds (i.e. 2 hours)
-      const MIN_DELAY = 1;  // 1 second
+      /** @const */ var MAX_DELAY = 7200;  // 7200 seconds (i.e. 2 hours)
+      /** @const */ var MIN_DELAY = 1;  // 1 second
 
       var delay = Math.pow(2, this.retryCount_) * 5;
       delay = Math.max(MIN_DELAY, Math.min(MAX_DELAY, delay)) * 1000;