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 29 matching lines @@
 using application_launch::LaunchParams;
 using application_launch::OpenApplication;
 using content::WebContents;
 using extensions::CrxInstaller;
 using extensions::Extension;
 using extensions::ExtensionPrefs;
 
 const net::UnescapeRule::Type kUnescapeRules =
     net::UnescapeRule::NORMAL | net::UnescapeRule::URL_SPECIAL_CHARS;
 
+AppsPagePresenceHandler::AppsPagePresenceHandler() {}
+
+AppsPagePresenceHandler::~AppsPagePresenceHandler() {}
+
+void AppsPagePresenceHandler::RegisterMessages() {
+  web_ui()->RegisterMessageCallback("getShouldShowApps",
+      base::Bind(&AppsPagePresenceHandler::HandleGetShouldShowApps,
+                 base::Unretained(this)));
+}
+
+void AppsPagePresenceHandler::HandleGetShouldShowApps(const ListValue* args) {
+  extensions::GetIsAppLauncherEnabled(
+      base::Bind(&AppsPagePresenceHandler::GotIsAppLauncherEnabled,
+                 base::Unretained(this)));
+}
+
+void AppsPagePresenceHandler::GotIsAppLauncherEnabled(bool is_enabled) {
+  PrefService* prefs = Profile::FromWebUI(web_ui())->GetPrefs();
+  prefs->SetBoolean(prefs::kNtpShouldShowAppsPage, !is_enabled);
+  base::FundamentalValue should_show_apps(!is_enabled);
+  web_ui()->CallJavascriptFunction("ntp.gotShouldShowApps", should_show_apps);
+}
+
 AppLauncherHandler::AppInstallInfo::AppInstallInfo() {}
 
 AppLauncherHandler::AppInstallInfo::~AppInstallInfo() {}
 
 AppLauncherHandler::AppLauncherHandler(ExtensionService* extension_service)
     : extension_service_(extension_service),
       ignore_changes_(false),
       attempted_bookmark_app_install_(false),
       has_loaded_apps_(false) {
 }
@@ skipping 696 matching lines @@
 void AppLauncherHandler::OnPreferenceChanged() {
   DictionaryValue dictionary;
   FillAppDictionary(&dictionary);
   web_ui()->CallJavascriptFunction("ntp.appsPrefChangeCallback", dictionary);
 }
 
 // static
 void AppLauncherHandler::RegisterUserPrefs(PrefServiceSyncable* pref_service) {
   pref_service->RegisterListPref(prefs::kNtpAppPageNames,
                                  PrefServiceSyncable::SYNCABLE_PREF);
+  pref_service->RegisterBooleanPref(prefs::kNtpShouldShowAppsPage,
+                                    true,

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

shouldn't this default to NewTabUI::ShouldShowApps()?

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

It should probably default to the result of just the synchronous checks in
extensions::GetIsAppLauncherEnabled, and NewTabUI::ShouldShowApps() should be
removed.

+                                    PrefServiceSyncable::UNSYNCABLE_PREF);
 }
 
 void AppLauncherHandler::CleanupAfterUninstall() {
   extension_id_prompting_.clear();
 }
 
 // static
 void AppLauncherHandler::RecordAppLaunchType(
     extension_misc::AppLaunchBucket bucket) {
   UMA_HISTOGRAM_ENUMERATION(extension_misc::kAppLaunchHistogram, bucket,
@@ skipping 91 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();
 }