Add a specialized apps::NativeAppWindow for app_shell

chrome/browser/apps/chrome_apps_client.cc

Index: chrome/browser/apps/chrome_apps_client.cc
diff --git a/chrome/browser/apps/chrome_apps_client.cc b/chrome/browser/apps/chrome_apps_client.cc
index 25d215365a02aee6058253bc2dc8fd995b085e36..8492f2eed9982d0b92e604c90e63f10d45c84284 100644
--- a/chrome/browser/apps/chrome_apps_client.cc
+++ b/chrome/browser/apps/chrome_apps_client.cc
@@ -4,10 +4,13 @@
 
 #include "chrome/browser/apps/chrome_apps_client.h"
 
+#include "apps/shell_window.h"
 #include "base/memory/singleton.h"
 #include "chrome/browser/browser_process.h"
+#include "chrome/browser/lifetime/application_lifetime.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/apps/app_metro_infobar_delegate_win.h"
+#include "chrome/browser/ui/apps/chrome_shell_window_delegate.h"
 #include "extensions/common/extension.h"
 
 #if defined(OS_WIN)
@@ -47,3 +50,18 @@ bool ChromeAppsClient::CheckAppLaunch(content::BrowserContext* context,
 #endif
   return true;
 }
+
+apps::ShellWindow* ChromeAppsClient::CreateShellWindow(
+    content::BrowserContext* context,
+    const extensions::Extension* extension) {
+  return new apps::ShellWindow(
+      context, new ChromeShellWindowDelegate, extension);
+}
+
+void ChromeAppsClient::StartKeepAlive() {
+  chrome::StartKeepAlive();
+}
+
+void ChromeAppsClient::EndKeepAlive() {
+  chrome::EndKeepAlive();
+}