Add a new App launcher promo to the apps page / NTP.

chrome/browser/resources/ntp4/page_list_view.js

 // Copyright (c) 2012 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 PageListView implementation.
  * PageListView manages page list, dot list, switcher buttons and handles apps
  * pages callbacks from backend.
  *
  * Note that you need to have AppLauncherHandler in your WebUI to use this code.
@@ skipping 394 matching lines @@
       logEvent('apps.layout: ' + (Date.now() - startTime));
 
       // Tell the slider about the pages and mark the current page.
       this.updateSliderCards();
       this.cardSlider.currentCardValue.navigationDot.classList.add('selected');
 
       if (!this.appsLoaded_) {
         this.appsLoaded_ = true;
         cr.dispatchSimpleEvent(document, 'sectionready', true, true);
       }
+      $('app-launcher-promo').hidden =
+        !loadTimeData.getBoolean('showAppLauncherPromo') ||
+        this.shownPage != loadTimeData.getInteger('apps_page_id');
     },
 
     /**
      * Called by chrome when a new app has been added to chrome or has been
      * enabled if previously disabled.
      * @param {Object} appData A data structure full of relevant information for
      *     the app.
      * @param {boolean=} opt_highlight Whether the app about to be added should
      *     be highlighted.
      */
@@ skipping 43 matching lines @@
 
       // Set the App dot names. Skip the first dot (Most Visited).
       var dots = this.dotList.getElementsByClassName('dot');
       var start = this.mostVisitedPage ? 1 : 0;
       for (var i = start; i < dots.length; ++i) {
         dots[i].displayTitle = data.appPageNames[i - start] || '';
       }
     },
 
     /**
+     * Callback invoked by chrome whenever the app launcher promo pref changes.
+     * @param {bool} show Identifies if we should show or hide the promo.

[Dan Beam, 2013/03/21 15:45:14]

{boolean}

[MAD, 2013/03/21 16:47:47]

Done.

+     */
+    appLauncherPromoPrefChangeCallback: function(show) {
+      $('app-launcher-promo').hidden = !show;
+      loadTimeData.overrideValues({'showAppLauncherPromo': show});

[Dan Beam, 2013/03/21 15:45:14]

nit: loadTimeData.overrideValues({showAppLauncherPromo: show});

[MAD, 2013/03/21 16:47:47]

Done.

+    },
+
+    /**
      * Invoked whenever the pages in apps-page-list have changed so that
      * the Slider knows about the new elements.
      */
     updateSliderCards: function() {
       var pageNo = Math.max(0, Math.min(this.cardSlider.currentCard,
                                         this.tilePages.length - 1));
       this.cardSlider.setCards(Array.prototype.slice.call(this.tilePages),
                                pageNo);
       switch (this.shownPage) {
         case loadTimeData.getInteger('apps_page_id'):
           this.cardSlider.selectCardByValue(
               this.appsPages[Math.min(this.shownPageIndex,
                                       this.appsPages.length - 1)]);
           break;
         case loadTimeData.getInteger('most_visited_page_id'):
-          if (this.mostVisitedPage)
+          if (this.mostVisitedPage) {
             this.cardSlider.selectCardByValue(this.mostVisitedPage);
+          } else if (loadTimeData.getBoolean('showApps')) {
+            // If we don't have a most visited page, we are likely on the
+            // chrome://apps page, so set it appropriately so that we can
+            // display the app launcher promo.
+            this.shownPage = loadTimeData.getInteger('apps_page_id');

[Dan Beam, 2013/03/21 15:45:14]

^ er, shouldn't you be selectCardByValue()'ing here?

[MAD, 2013/03/21 16:47:47]

Yeah, I wasn't sure... Things seems to work anyway, so I tried to make a minimal
change for what wasn't working, i.e., the shownPage state which I need to decide
whether I show the promo box... Now that you asked for it, I changed it, and it
still works... So... fingers crossed... :-)

+          }
           break;
         case loadTimeData.getInteger('suggestions_page_id'):
           if (this.suggestionsPage)
             this.cardSlider.selectCardByValue(this.suggestionsPage);
+          else if (this.mostVisitedPage)
+            this.shownPage = loadTimeData.getInteger('most_visited_page_id');
+          else if (loadTimeData.getBoolean('showApps'))
+            this.shownPage = loadTimeData.getInteger('apps_page_id');
           break;
       }
     },
 
     /**
      * Called whenever tiles should be re-arranging themselves out of the way
      * of a moving or insert tile.
      */
     enterRearrangeMode: function() {
       if (loadTimeData.getBoolean('showApps')) {
@@ skipping 135 matching lines @@
      * Saves/updates the newly selected page to open when first loading the NTP.
      * @type {number} shownPage The new shown page type.
      * @type {number} shownPageIndex The new shown page index.
      * @private
      */
     setShownPage_: function(shownPage, shownPageIndex) {
       assert(shownPageIndex >= 0);
       this.shownPage = shownPage;
       this.shownPageIndex = shownPageIndex;
       chrome.send('pageSelected', [this.shownPage, this.shownPageIndex]);
+      $('app-launcher-promo').hidden =
+        !loadTimeData.getBoolean('showAppLauncherPromo') ||
+        this.shownPage != loadTimeData.getInteger('apps_page_id');

[Dan Beam, 2013/03/21 15:45:14]

please combine this and the same code above into a function and call from both
places

[MAD, 2013/03/21 16:47:47]

Done.
And it made me realize that if we would change the Pref back to true (which
currently can't happen, but might eventually), then we would have been able to
show the promo on non-Apps pages... Good catch! :-)

     },
 
     /**
      * Listen for card additions to update the page switchers or the current
      * card accordingly.
      * @param {Event} e A card removed or added event.
      */
     onCardAdded_: function(e) {
       // When the second arg passed to insertBefore is falsey, it acts just like
       // appendChild.
@@ skipping 105 matching lines @@
       if (page.navigationDot)
         page.navigationDot.remove(opt_animate);
       this.cardSlider.removeCard(page);
     },
   };
 
   return {
     PageListView: PageListView
   };
 });