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

chrome/browser/extensions/extension_process_manager.cc

Index: chrome/browser/extensions/extension_process_manager.cc
diff --git a/chrome/browser/extensions/extension_process_manager.cc b/chrome/browser/extensions/extension_process_manager.cc
index 6a2a88f720126915fbdb8b8eb973fe0726d4bbe3..ffd661a684e7dba079969f86884a90b7de7ae8f3 100644
--- a/chrome/browser/extensions/extension_process_manager.cc
+++ b/chrome/browser/extensions/extension_process_manager.cc
@@ -11,6 +11,7 @@
 #include "base/string_number_conversions.h"
 #include "base/time.h"
 #include "chrome/browser/extensions/api/runtime/runtime_api.h"
+#include "chrome/browser/extensions/app_extension_host_delegate.h"
 #include "chrome/browser/extensions/extension_process_manager.h"
 #include "chrome/browser/extensions/extension_host.h"
 #include "chrome/browser/extensions/extension_info_map.h"
@@ -217,9 +218,11 @@ ExtensionHost* ExtensionProcessManager::CreateViewHost(
   ExtensionHost* host =
 #if defined(OS_MACOSX)
       new extensions::ExtensionHostMac(
-          extension, GetSiteInstanceForURL(url), url, view_type);
+          extension,  new ExtensionHost::Delegate(),
+          GetSiteInstanceForURL(url), url, view_type);
 #else
-      new ExtensionHost(extension, GetSiteInstanceForURL(url), url, view_type);
+      new ExtensionHost(extension, new ExtensionHost::Delegate(),
+                        GetSiteInstanceForURL(url), url, view_type);
 #endif
   host->CreateView(browser);
   OnExtensionHostCreated(host, false);
@@ -280,14 +283,20 @@ void ExtensionProcessManager::CreateBackgroundHost(
   if (GetBackgroundHostForExtension(extension->id()))
     return;
 
+  ExtensionHost::Delegate* host_delegate;
+  if (extension->is_platform_app())
+    host_delegate = new extensions::AppBackgroundHostDelegate();
+  else
+    host_delegate = new ExtensionHost::Delegate();
+
   ExtensionHost* host =
 #if defined(OS_MACOSX)
       new extensions::ExtensionHostMac(
-          extension, GetSiteInstanceForURL(url), url,
+          extension, host_delegate, GetSiteInstanceForURL(url), url,
           chrome::VIEW_TYPE_EXTENSION_BACKGROUND_PAGE);
 #else
-      new ExtensionHost(extension, GetSiteInstanceForURL(url), url,
-                        chrome::VIEW_TYPE_EXTENSION_BACKGROUND_PAGE);
+      new ExtensionHost(extension, host_delegate, GetSiteInstanceForURL(url),
+                        url, chrome::VIEW_TYPE_EXTENSION_BACKGROUND_PAGE);
 #endif
 
   host->CreateRenderViewSoon();