Add a specialized apps::NativeAppWindow for app_shell

apps/apps_client.h

 // Copyright 2013 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.
 
 #ifndef APPS_APPS_CLIENT_H_
 #define APPS_APPS_CLIENT_H_
 
 #include <vector>
 
 namespace content {
 class BrowserContext;
 }
 
 namespace extensions {
 class Extension;
 }
 
 namespace apps {
 
+class ShellWindow;
+
 // Sets up global state for the apps system. Should be Set() once in each
 // process. This should be implemented by the client of the apps system.
 class AppsClient {
  public:
   // Get all loaded browser contexts.
   virtual std::vector<content::BrowserContext*> GetLoadedBrowserContexts() = 0;
 
   // Do any pre app launch checks. Returns true if the app launch should proceed
   // or false if the launch should be prevented.
   virtual bool CheckAppLaunch(content::BrowserContext* context,
                               const extensions::Extension* extension) = 0;
 
+  // Creates a new apps::ShellWindow for the app in |extension| for |context|.
+  // Caller takes ownership.
+  virtual ShellWindow* CreateShellWindow(

[James Cook, 2014/02/13 01:13:36]

I really only need the delegate, but I elected to return ShellWindow because it
can be forward declared. I can extract ShellWindow::Delegate to its own class,
but that will also require extracting ShellWindow::CreateParams to its own class
and doing that felt a little big for this CL.

+      content::BrowserContext* context,
+      const extensions::Extension* extension) = 0;
+
+  // Tells the embedding application to stay running. The application may close
+  // after a matching number of calls to EndKeepAlive() are made.
+  virtual void StartKeepAlive() = 0;
+  virtual void EndKeepAlive() = 0;
+
   // Return the apps client.
   static AppsClient* Get();
 
   // Initialize the apps system with this apps client.
   static void Set(AppsClient* client);
 };
 
 }  // namespace apps
 
 #endif  // APPS_APPS_CLIENT_H_