First cut at "content handling" support in Mojo.

mojo/service_manager/background_service_loader.h

Index: mojo/service_manager/background_service_loader.h
diff --git a/mojo/service_manager/background_service_loader.h b/mojo/service_manager/background_service_loader.h
index 253637adb6cfefb487ebce1db7fee5276561e98b..5ff7141c9f0c7cd08426468d821b2dd500f3f068 100644
--- a/mojo/service_manager/background_service_loader.h
+++ b/mojo/service_manager/background_service_loader.h
@@ -25,9 +25,10 @@ class MOJO_SERVICE_MANAGER_EXPORT BackgroundServiceLoader
   virtual ~BackgroundServiceLoader();
 
   // ServiceLoader overrides:
-  virtual void LoadService(ServiceManager* manager,
-                           const GURL& url,
-                           ScopedMessagePipeHandle shell_handle) OVERRIDE;
+  virtual void LoadService(
+      ServiceManager* manager,
+      const GURL& url,
+      scoped_refptr<LoadServiceCallbacks> callbacks) OVERRIDE;
   virtual void OnServiceError(ServiceManager* manager,
                               const GURL& url) OVERRIDE;
 
@@ -41,7 +42,7 @@ class MOJO_SERVICE_MANAGER_EXPORT BackgroundServiceLoader
   void LoadServiceOnBackgroundThread(
       ServiceManager* manager,
       const GURL& url,
-      ScopedMessagePipeHandle* shell_handle);
+      ScopedMessagePipeHandle shell_handle);
   void OnServiceErrorOnBackgroundThread(ServiceManager* manager,
                                         const GURL& url);
   void ShutdownOnBackgroundThread();