Keep browser process alive while there are platform apps with background pages running.

chrome/browser/extensions/extension_host.h

 // 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_EXTENSION_HOST_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_HOST_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 111 matching lines @@
   void CreateRenderViewSoon();
 
   // Insert a default style sheet for Extension Infobars.
   void InsertInfobarCSS();
 
   // Notifications from the JavaScriptDialogCreator when a dialog is being
   // opened/closed.
   void WillRunJavaScriptDialog();
   void DidCloseJavaScriptDialog();
 
+  // This is called on hosts which need to keep the browser process alive. This
+  // function will add a browser process keep alive, if it hasn't already been
+  // added. Hosts which have had this called will remove the keep alive when
+  // they are destroyed.
+  void KeepBrowserProcessAlive();
+
   // content::WebContentsObserver
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
   virtual void RenderViewCreated(
       content::RenderViewHost* render_view_host) OVERRIDE;
   virtual void RenderViewDeleted(
       content::RenderViewHost* render_view_host) OVERRIDE;
   virtual void RenderViewReady() OVERRIDE;
   virtual void RenderViewGone(base::TerminationStatus status) OVERRIDE;
   virtual void DocumentAvailableInMainFrame() OVERRIDE;
   virtual void DidStopLoading(
@@ skipping 99 matching lines @@
   // this through the host_contents because we want to deal with the pending
   // host, so we can send messages to it before it finishes loading.
   content::RenderViewHost* render_view_host_;
 
   // Whether the RenderWidget has reported that it has stopped loading.
   bool did_stop_loading_;
 
   // True if the main frame has finished parsing.
   bool document_element_available_;
 
+  // If true, the browser process has had a keep alive added for this host.
+  bool keeping_browser_process_alive_;
+
   // The original URL of the page being hosted.
   GURL initial_url_;
 
   content::NotificationRegistrar registrar_;
 
   ExtensionFunctionDispatcher extension_function_dispatcher_;
 
   // The type of view being hosted.
   chrome::ViewType extension_host_type_;
 
   // The relevant WebContents associated with this ExtensionHost, if any.
   content::WebContents* associated_web_contents_;
 
   // Used to measure how long it's been since the host was created.
   PerfTimer since_created_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionHost);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_HOST_H_