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 200 matching lines @@
           this.updateOfflineEnabledApps_.bind(this));
       window.addEventListener('offline',
           this.updateOfflineEnabledApps_.bind(this));
     },
 
     /**
      * Appends a tile page.
      *
      * @param {TilePage} page The page element.
      * @param {string} title The title of the tile page.
-     * @param {bool} titleIsEditable If true, the title can be changed.
+     * @param {boolean} titleIsEditable If true, the title can be changed.
      * @param {TilePage} opt_refNode Optional reference node to insert in front
      *     of.
      * When opt_refNode is falsey, |page| will just be appended to the end of
      * the page list.
      */
     appendTilePage: function(page, title, titleIsEditable, opt_refNode) {
       if (opt_refNode) {
         var refIndex = this.getTilePageIndex(opt_refNode);
         this.cardSlider.addCardAtIndex(page, refIndex);
       } else {
@@ skipping 173 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);
       }
+      this.updateAppLauncherPromoHiddenState_();
     },
 
     /**
      * 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 {boolean} show Identifies if we should show or hide the promo.
+     */
+    appLauncherPromoPrefChangeCallback: function(show) {
+      loadTimeData.overrideValues({showAppLauncherPromo: show});
+      this.updateAppLauncherPromoHiddenState_();
+    },
+
+    /**
+     * Updates the hidden state of the app launcher promo based on the page
+     * shown and load data content.
+     */
+    updateAppLauncherPromoHiddenState_: function() {
+      $('app-launcher-promo').hidden =
+          !loadTimeData.getBoolean('showAppLauncherPromo') ||
+          this.shownPage != loadTimeData.getInteger('apps_page_id');
+    },
+
+    /**
      * 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)
-            this.cardSlider.selectCardByValue(this.mostVisitedPage);
-          break;
-        case loadTimeData.getInteger('suggestions_page_id'):
-          if (this.suggestionsPage)
-            this.cardSlider.selectCardByValue(this.suggestionsPage);
-          break;
+      // The shownPage property was potentially saved from a previous webui that
+      // didn't have the same set of pages as the current one. So we cascade
+      // from suggestions, to most visited and then to apps because we can have
+      // an page with apps only (e.g., chrome://apps) or one with only the most
+      // visited, but not one with only suggestions. And we alwayd default to
+      // most visited first when previously shown page is not availabel anymore.
+      // If most visited isn't there either, we go to apps.
+      if (this.shownPage == loadTimeData.getInteger('suggestions_page_id')) {
+        if (this.suggestionsPage)
+          this.cardSlider.selectCardByValue(this.suggestionsPage);
+        else
+          this.shownPage = loadTimeData.getInteger('most_visited_page_id');
+      }
+      if (this.shownPage == loadTimeData.getInteger('most_visited_page_id')) {
+        if (this.mostVisitedPage)
+          this.cardSlider.selectCardByValue(this.mostVisitedPage);
+        else
+          this.shownPage = loadTimeData.getInteger('apps_page_id');
+      }
+      if (this.shownPage == loadTimeData.getInteger('apps_page_id') &&
+          loadTimeData.getBoolean('showApps')) {
+        this.cardSlider.selectCardByValue(
+            this.appsPages[Math.min(this.shownPageIndex,
+                                    this.appsPages.length - 1)]);
+      } else if (this.mostVisitedPage) {
+        this.shownPage = loadTimeData.getInteger('most_visited_page_id');
+        this.cardSlider.selectCardByValue(this.mostVisitedPage);
       }
     },
 
     /**
      * Called whenever tiles should be re-arranging themselves out of the way
      * of a moving or insert tile.
      */
     enterRearrangeMode: function() {
       if (loadTimeData.getBoolean('showApps')) {
         var tempPage = new ntp.AppsPage();
@@ skipping 134 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]);
+      this.updateAppLauncherPromoHiddenState_();
     },
 
     /**
      * 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
   };
 });