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

chrome/browser/ui/webui/ntp/app_launcher_handler.cc

 // 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.
 
 #include "chrome/browser/ui/webui/ntp/app_launcher_handler.h"
 
 #include <vector>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/i18n/rtl.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
+#include "chrome/browser/extensions/app_launcher.h"
 #include "chrome/browser/extensions/app_notification.h"
 #include "chrome/browser/extensions/app_notification_manager.h"
 #include "chrome/browser/extensions/crx_installer.h"
 #include "chrome/browser/extensions/extension_prefs.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_sorting.h"
 #include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/extensions/management_policy.h"
 #include "chrome/browser/favicon/favicon_service_factory.h"
 #include "chrome/browser/prefs/pref_service.h"
@@ skipping 144 matching lines @@
         sorting->CreateNextAppLaunchOrdinal(page_ordinal);
     sorting->SetAppLaunchOrdinal(extension->id(), app_launch_ordinal);
   }
   value->SetString("app_launch_ordinal", app_launch_ordinal.ToInternalValue());
 }
 
 void AppLauncherHandler::RegisterMessages() {
   registrar_.Add(this, chrome::NOTIFICATION_APP_INSTALLED_TO_NTP,
       content::Source<WebContents>(web_ui()->GetWebContents()));
 
+  web_ui()->RegisterMessageCallback("getShouldShowApps",
+      base::Bind(&AppLauncherHandler::HandleGetShouldShowApps,
+                 base::Unretained(this)));
   web_ui()->RegisterMessageCallback("getApps",
       base::Bind(&AppLauncherHandler::HandleGetApps,
                  base::Unretained(this)));
   web_ui()->RegisterMessageCallback("launchApp",
       base::Bind(&AppLauncherHandler::HandleLaunchApp,
                  base::Unretained(this)));
   web_ui()->RegisterMessageCallback("setLaunchType",
       base::Bind(&AppLauncherHandler::HandleSetLaunchType,
                  base::Unretained(this)));
   web_ui()->RegisterMessageCallback("uninstallApp",
@@ skipping 44 matching lines @@
           *content::Details<const std::string>(details).ptr();
       const extensions::AppNotification* notification =
           extension_service_->app_notification_manager()->GetLast(id);
       base::StringValue id_value(id);
       if (notification) {
         scoped_ptr<DictionaryValue> notification_value(
             SerializeNotification(*notification));
         web_ui()->CallJavascriptFunction("ntp.appNotificationChanged",
             id_value, *notification_value.get());
       } else {
         web_ui()->CallJavascriptFunction("ntp.appNotificationChanged",

[Evan Stade, 2013/01/24 18:40:17]

now that you're always including the app launcher handler, won't calls like this
wind up causing errors on the NTP?

[jeremya, 2013/01/25 00:06:19]

Good catch. Moved to new_tab_page_handler.

                                          id_value);
       }
       break;
     }
 
     case chrome::NOTIFICATION_EXTENSION_LOADED: {
       const Extension* extension =
           content::Details<const Extension>(details).ptr();
       if (!extension->is_app())
         return;
@@ skipping 127 matching lines @@
   DictionaryValue* app_info = new DictionaryValue();
   // CreateAppInfo can change the extension prefs.
   base::AutoReset<bool> auto_reset(&ignore_changes_, true);
   CreateAppInfo(extension,
                 notification_manager->GetLast(extension->id()),
                 extension_service_,
                 app_info);
   return app_info;
 }
 
+void AppLauncherHandler::HandleGetShouldShowApps(const ListValue* args) {
+  extensions::UpdateIsAppLauncherEnabled(
+      base::Bind(&AppLauncherHandler::GotIsAppLauncherEnabled,
+                 base::Unretained(this)));

[Evan Stade, 2013/01/24 18:40:17]

this doesn't seem right. You need to pass a weak pointer.

[jeremya, 2013/01/25 00:06:19]

Done.

+}
+
+void AppLauncherHandler::GotIsAppLauncherEnabled(bool is_enabled) {
+  base::FundamentalValue should_show_apps(!is_enabled);
+  web_ui()->CallJavascriptFunction("ntp.gotShouldShowApps", should_show_apps);
+}
+
 void AppLauncherHandler::HandleGetApps(const ListValue* args) {
   DictionaryValue dictionary;
 
   // Tell the client whether to show the promo for this view. We don't do this
   // in the case of PREF_CHANGED because:
   //
   // a) At that point in time, depending on the pref that changed, it can look
   //    like the set of apps installed has changed, and we will mark the promo
   //    expired.
   // b) Conceptually, it doesn't really make sense to count a
@@ skipping 480 matching lines @@
 
 ExtensionUninstallDialog* AppLauncherHandler::GetExtensionUninstallDialog() {
   if (!extension_uninstall_dialog_.get()) {
     Browser* browser = chrome::FindBrowserWithWebContents(
         web_ui()->GetWebContents());
     extension_uninstall_dialog_.reset(
         ExtensionUninstallDialog::Create(browser, this));
   }
   return extension_uninstall_dialog_.get();
 }