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

chrome/browser/ui/webui/ntp/app_launcher_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_APP_LAUNCHER_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_NTP_APP_LAUNCHER_HANDLER_H_
 
 #include <set>
 #include <string>
 
@@ skipping 13 matching lines @@
 class ExtensionEnableFlow;
 class ExtensionService;
 class PrefChangeRegistrar;
 class PrefServiceSyncable;
 class Profile;
 
 namespace extensions {
 class AppNotification;
 }
 
+class AppsPagePresenceHandler : public content::WebUIMessageHandler {

[Evan Stade, 2013/01/23 23:34:24]

why is this separate from AppLauncherHandler?

[jeremya, 2013/01/24 02:40:04]

Because AppLauncherHandler isn't always present. Previously this was required
because if the NTP didn't receive the gotShouldShowApps message it wouldn't
load, but since it loads opportunistically now, this can probably be rolled into
AppLauncherHandler.

+ public:
+  AppsPagePresenceHandler();
+  virtual ~AppsPagePresenceHandler();
+
+  // WebUIMessageHandler implementation.
+  virtual void RegisterMessages() OVERRIDE;
+
+  // Callback for the "getShouldShowApps" message.
+  void HandleGetShouldShowApps(const base::ListValue* args);
+
+ private:
+  // Callback for extensions::GetIsAppLauncherEnabled().
+  void GotIsAppLauncherEnabled(bool is_enabled);
+
+  DISALLOW_COPY_AND_ASSIGN(AppsPagePresenceHandler);
+};
+
 // The handler for Javascript messages related to the "apps" view.
 class AppLauncherHandler : public content::WebUIMessageHandler,
                            public ExtensionUninstallDialog::Delegate,
                            public ExtensionEnableFlowDelegate,
                            public content::NotificationObserver {
  public:
   explicit AppLauncherHandler(ExtensionService* extension_service);
   virtual ~AppLauncherHandler();
 
   // Populate a dictionary with the information from an extension.
@@ skipping 157 matching lines @@
   // when the app is added to the page (via getAppsCallback or appAdded).
   std::string highlight_app_id_;
 
   // Used for favicon loading tasks.
   CancelableTaskTracker cancelable_task_tracker_;
 
   DISALLOW_COPY_AND_ASSIGN(AppLauncherHandler);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_NTP_APP_LAUNCHER_HANDLER_H_