Add a sign-in promo message to the Other Devices menu.

chrome/browser/resources/ntp4/other_sessions.js

Index: chrome/browser/resources/ntp4/other_sessions.js
diff --git a/chrome/browser/resources/ntp4/other_sessions.js b/chrome/browser/resources/ntp4/other_sessions.js
index ccd693d67b8f1385a813ace1e3733ac51e0199bf..cd9ffc1fb7aa21dc7174e38fa70c74afc00c7fb4 100644
--- a/chrome/browser/resources/ntp4/other_sessions.js
+++ b/chrome/browser/resources/ntp4/other_sessions.js
@@ -24,6 +24,8 @@ cr.define('ntp', function() {
   };
   var HISTOGRAM_EVENT_LIMIT = HISTOGRAM_EVENT.LINK_RIGHT_CLICKED + 1;
 

[Dan Beam, 2012/03/26 20:42:39]

can you document when/where this will be changed

[Patrick Dubroy, 2012/03/26 21:41:47]

Done.

+  var isUserSignedIn = false;
+
   OtherSessionsMenuButton.prototype = {
     __proto__: MenuButton.prototype,
 
@@ -36,15 +38,26 @@ cr.define('ntp', function() {
                                  this.onContextMenu_.bind(this), true);
       document.body.appendChild(this.menu);
 
+      // Put the promo content (hidden by default) into the menu.
+      var messageContent = $('other-sessions-promo-message');
+      this.menu.appendChild(messageContent);

[Dan Beam, 2012/03/26 20:42:39]

nit: inline this

  this.menu.appendChild($('other-sessions-promo-message'));

or simply call .resetMenu_() ?

[Patrick Dubroy, 2012/03/26 21:41:47]

Done.

+
       this.sessions_ = [];
       this.anchorType = cr.ui.AnchorType.ABOVE;
       this.invertLeftRight = true;
 
-      chrome.send('getForeignSessions');
       this.recordUmaEvent_(HISTOGRAM_EVENT.INITIALIZED);
     },
 
     /**
+     * Initialize this element.
+     * @param {boolean} signedIn Is the current user signed in?
+     */
+    initialize: function(signedIn) {
+      this.updateSignInState(signedIn);
+    },
+
+    /**
      * Record an event in the UMA histogram.
      * @param {Number} eventId The id of the event to be recorded.
      */
@@ -76,6 +89,16 @@ cr.define('ntp', function() {
     },
 
     /**
+     * Reset the menu to the default state.

[Dan Beam, 2012/03/26 20:42:39]

@private

[Patrick Dubroy, 2012/03/26 21:41:47]

Done.

+     */
+    resetMenu_: function() {
+      var promoContent = $('other-sessions-promo-message');
+      this.menu.innerHTML = '';
+      this.menu.appendChild(promoContent);
+      promoContent.hidden = true;
+    },
+
+    /**
      * Create a custom click handler for a link, so that clicking on a link
      * restores the session (including back stack) rather than just opening
      * the URL.
@@ -122,35 +145,45 @@ cr.define('ntp', function() {
     },
 
     /**
-     * Create the UI for the promo and place it inside the menu.
-     * The promo is shown instead of foreign session data when tab sync is
-     * not enabled for a profile.
+     * Show or hide the promo message shown in place of the session list.
+     * The promo is shown when the user is signed in, but there is no foreign
+     * session data available.
+     * @param {boolean} visible Whether the message should be shown.

[Dan Beam, 2012/03/26 20:42:39]

@private

[Patrick Dubroy, 2012/03/26 21:41:47]

Done.

      */
-    showPromo_: function() {
-      var message = localStrings.getString('otherSessionsEmpty');
-      this.menu.appendChild(this.ownerDocument.createTextNode(message));
+    setPromoVisible_: function(visible) {
+      this.resetMenu_();
+      $('other-sessions-promo-message').hidden = !visible;
     },
 
     /**
      * Sets the menu model data.
      * @param {Array} sessionList Array of objects describing the sessions
-     * from other devices.
+     *     from other devices.
      */
     set sessions(sessionList) {
-      // Clear the current contents of the menu.
-      this.menu.innerHTML = '';
-
-      // Rebuild the menu with the new data.
-      for (var i = 0; i < sessionList.length; i++) {
-        this.addSession_(sessionList[i]);
+      this.sessions_ = sessionList;
+      this.setPromoVisible_(sessionList.length == 0);
+      if (sessionList.length > 0) {
+        // Rebuild the menu with the new data.
+        for (var i = 0; i < sessionList.length; i++) {
+          this.addSession_(sessionList[i]);
+        }
       }
+      // Make the menu button visible.
+      this.classList.remove('invisible');
+    },
 
-      if (sessionList.length == 0)
-        this.classList.add('invisible');
-      else
-        this.classList.remove('invisible');
+    /**
+     * Called from the new tab page when the user's signed in state changes.
+     * @param {boolean} signedIn Is the user currently signed in?
+     */
+    updateSignInState: function(signedIn) {

[Dan Beam, 2012/03/26 20:42:39]

if this is called nowhere else outside of this function, make private_ /
@private

[Patrick Dubroy, 2012/03/26 21:41:47]

It's called from the ntp.js when the sign-in state changes.

+      isUserSignedIn = signedIn;
 
-      this.sessions_ = sessionList;
+      if (signedIn)
+        chrome.send('getForeignSessions');
+      else
+        this.classList.add('invisible');
     },
   };