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

chrome/browser/extensions/extension_browsertest.h

Index: chrome/browser/extensions/extension_browsertest.h
diff --git a/chrome/browser/extensions/extension_browsertest.h b/chrome/browser/extensions/extension_browsertest.h
index b1e82a0b1a999f6dbd8402fbfa603ab36b55c32f..7affc4936d36faae95ec4ae73b9ddb73e9c8557e 100644
--- a/chrome/browser/extensions/extension_browsertest.h
+++ b/chrome/browser/extensions/extension_browsertest.h
@@ -22,6 +22,7 @@
 #include "content/public/browser/web_contents.h"
 
 class ExtensionProcessManager;
+class ShellWindow;
 
 // Base class for extension browser tests. Provides utilities for loading,
 // unloading, and installing extensions.
@@ -169,6 +170,13 @@ class ExtensionBrowserTest : virtual public InProcessBrowserTest,
   // Wait for the crx installer to be done. Returns true if it really is done.
   bool WaitForCrxInstallerDone();
 
+  // Closes |window| and waits until it's gone.
+  void CloseShellWindow(ShellWindow* window);
+
+  // Close any Shell Windows and wait for the app's background page to be
+  // unloaded.
+  void CloseShellWindowsAndWaitForAppToExit();
+
   // Simulates a page calling window.open on an URL and waits for the
   // navigation.
   void OpenWindow(content::WebContents* contents,