Hidden windows should not keep Chrome alive.

chrome/browser/ui/apps/chrome_app_delegate.h

 // Copyright 2014 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 CHROME_BROWSER_UI_APPS_CHROME_APP_DELEGATE_H_
 #define CHROME_BROWSER_UI_APPS_CHROME_APP_DELEGATE_H_
 
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "extensions/browser/app_window/app_delegate.h"
 #include "ui/base/window_open_disposition.h"
 #include "ui/gfx/geometry/rect.h"
 
 class ScopedKeepAlive;
 
 class ChromeAppDelegate : public extensions::AppDelegate,
                           public content::NotificationObserver {
  public:
   // Pass a ScopedKeepAlive to prevent the browser process from shutting down
   // while this object exists.
   explicit ChromeAppDelegate(scoped_ptr<ScopedKeepAlive> keep_alive);
   ~ChromeAppDelegate() override;
 
   static void DisableExternalOpenForTesting();
 
  private:
+  static void RelinquishKeepAliveAfterTimeout(
+      const base::WeakPtr<ChromeAppDelegate>& chrome_app_delegate);
+
   class NewWindowContentsDelegate;
 
   // extensions::AppDelegate:
   void InitWebContents(content::WebContents* web_contents) override;
   void RenderViewCreated(content::RenderViewHost* render_view_host) override;
   void ResizeWebContents(content::WebContents* web_contents,
                          const gfx::Size& size) override;
   content::WebContents* OpenURLFromTab(
       content::BrowserContext* context,
       content::WebContents* source,
@@ skipping 16 matching lines @@
   bool CheckMediaAccessPermission(
       content::WebContents* web_contents,
       const GURL& security_origin,
       content::MediaStreamType type,
       const extensions::Extension* extension) override;
   int PreferredIconSize() override;
   void SetWebContentsBlocked(content::WebContents* web_contents,
                              bool blocked) override;
   bool IsWebContentsVisible(content::WebContents* web_contents) override;
   void SetTerminatingCallback(const base::Closure& callback) override;
+  void OnHide() override;
+  void OnShow() override;
 
   // content::NotificationObserver:
   void Observe(int type,
                const content::NotificationSource& source,
                const content::NotificationDetails& details) override;
 
+  bool has_been_shown_;
+  bool is_hidden_;
   scoped_ptr<ScopedKeepAlive> keep_alive_;
   scoped_ptr<NewWindowContentsDelegate> new_window_contents_delegate_;
   base::Closure terminating_callback_;
   content::NotificationRegistrar registrar_;
+  base::WeakPtrFactory<ChromeAppDelegate> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeAppDelegate);
 };
 
 #endif  // CHROME_BROWSER_UI_APPS_CHROME_APP_DELEGATE_H_