Create a new chrome/browser/apps folder and move PlatformAppService there.

chrome/browser/extensions/platform_app_service.cc

Index: chrome/browser/extensions/platform_app_service.cc
diff --git a/chrome/browser/extensions/platform_app_service.cc b/chrome/browser/extensions/platform_app_service.cc
deleted file mode 100644
index 29c8aae37f195f9f8c93df1d41874a1b6e0f306b..0000000000000000000000000000000000000000
--- a/chrome/browser/extensions/platform_app_service.cc
+++ /dev/null
@@ -1,39 +0,0 @@
-// 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/extensions/platform_app_service.h"
-
-#include "chrome/browser/extensions/extension_host.h"
-#include "chrome/common/chrome_notification_types.h"
-#include "chrome/common/extensions/extension.h"
-#include "content/public/browser/browser_context.h"
-#include "content/public/browser/notification_details.h"
-#include "content/public/browser/notification_service.h"
-#include "content/public/browser/notification_types.h"
-
-namespace extensions {
-
-PlatformAppService::PlatformAppService(Profile* profile) {
-  registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_HOST_CREATED,
-                 content::Source<content::BrowserContext>(profile));
-}
-
-PlatformAppService::~PlatformAppService() {}
-
-void PlatformAppService::Observe(int type,
-                                  const content::NotificationSource& source,
-                                  const content::NotificationDetails& details) {
-  switch (type) {
-    case chrome::NOTIFICATION_EXTENSION_HOST_CREATED: {
-      ExtensionHost* host = content::Details<ExtensionHost>(details).ptr();
-      if (host->extension()->is_platform_app())
-        host->SetKeepsBrowserProcessAlive();
-      break;
-    }
-    default:
-      NOTREACHED();
-    }
-}
-
-}  // namespace extensions