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

chrome/browser/extensions/extension_host.h

Index: chrome/browser/extensions/extension_host.h
diff --git a/chrome/browser/extensions/extension_host.h b/chrome/browser/extensions/extension_host.h
index 9c0e247edbde463b6c5c8d13070f2ed54617f4c1..0e5bdbc985c30a8f88b186748a18019dfa8d4c8a 100644
--- a/chrome/browser/extensions/extension_host.h
+++ b/chrome/browser/extensions/extension_host.h
@@ -129,6 +129,12 @@ class ExtensionHost : public content::WebContentsDelegate,
   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 SetKeepsBrowserProcessAlive();
+
   // content::WebContentsObserver
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
   virtual void RenderViewCreated(
@@ -245,6 +251,9 @@ class ExtensionHost : public content::WebContentsDelegate,
   // 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_;