Make application shortcuts point to app_host.exe, install App Host during app installation.

chrome/browser/extensions/app_host_installer.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/extensions/app_host_installer.h"
+
+#include "base/callback.h"
+
+#if defined(OS_WIN)
+#include "chrome/browser/extensions/app_host_installer_impl_win.h"
+#endif
+
+namespace extensions {
+
+class Extension;
+
+namespace app_host_installer {
+
+void InstallAppHostIfNecessary(const Extension& extension,
+    const base::Callback<void(bool)>& completion_callback) {
+#if defined(OS_WIN)
+  // The implementation.

[erikwright (departed), 2012/10/09 19:24:48]

Go ahead and do the is_platform_app() check here, and then don't pass extension
to impl

[huangs, 2012/10/09 21:09:15]

Done.

+  AppHostInstallerImpl* impl = new AppHostInstallerImpl();

[erikwright (departed), 2012/10/09 19:24:48]

Make the constructor and destructor of AppHostInstallerImpl private, make
InstallAppHostIfNecessary a static function.

[huangs, 2012/10/09 21:09:15]

Nice. Done.

+  impl->InstallAppHostIfNecessary(extension, completion_callback);
+  // impl will handle its own destruction.
+#else
+  completion_callback.Run(true);
+#endif
+}
+
+}  // namespace app_host_installer
+
+}  // namespace extensions