Don't show the apps page on the NTP if the app launcher is installed.

chrome/browser/ui/webui/ntp/new_tab_page_handler.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_WEBUI_NTP_NEW_TAB_PAGE_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_NTP_NEW_TAB_PAGE_HANDLER_H_
 
+#include "base/memory/weak_ptr.h"
 #include "base/values.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "content/public/browser/web_ui_message_handler.h"
 
 class PrefServiceSimple;
 class PrefServiceSyncable;
 class Profile;
 
 // Handler for general New Tab Page functionality that does not belong in a
 // more specialized handler.
-class NewTabPageHandler : public content::WebUIMessageHandler {
+class NewTabPageHandler : public content::WebUIMessageHandler,
+                          public base::SupportsWeakPtr<NewTabPageHandler> {
  public:
   NewTabPageHandler();
 
   // Register NTP per-profile preferences.
   static void RegisterUserPrefs(PrefServiceSyncable* prefs);
 
   // Registers values (strings etc.) for the page.
   static void GetLocalizedValues(Profile* profile, DictionaryValue* values);
 
  private:
@@ skipping 19 matching lines @@
 
   // Callback for "bubblePromoLinkClicked". No arguments.
   void HandleBubblePromoLinkClicked(const ListValue* args);
 
   // Callback for "pageSelected".
   void HandlePageSelected(const ListValue* args);
 
   // Callback for "logTimeToClick".
   void HandleLogTimeToClick(const base::ListValue* args);
 
+  // Callback for the "getShouldShowApps" message.
+  void HandleGetShouldShowApps(const base::ListValue* args);
+
+  // Callback from extensions::UpdateIsAppLauncherEnabled().
+  void GotIsAppLauncherEnabled(bool is_enabled);
+
   // Tracks the number of times the user has switches pages (for UMA).
   size_t page_switch_count_;
 
   // The purpose of this enum is to track which page on the NTP is showing.
   // The lower 10 bits of kNtpShownPage are used for the index within the page
   // group, and the rest of the bits are used for the page group ID (defined
   // here).
   static const int kPageIdOffset = 10;
   // TODO(vadimt): create a new enum and a new UMA histogram for search ntp so
   // the two histograms don't get mixed in together.
@@ skipping 10 matching lines @@
   static const int kHistogramEnumerationMax =
       (LAST_PAGE_ID >> kPageIdOffset) + 1;
 
   // Helper to send out promo resource change notification.
   void Notify(chrome::NotificationType notification_type);
 
   DISALLOW_COPY_AND_ASSIGN(NewTabPageHandler);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_NTP_NEW_TAB_PAGE_HANDLER_H_