First cut at "content handling" support in Mojo.

mojo/service_manager/background_service_loader.h

 // Copyright 2014 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 MOJO_SERVICE_MANAGER_BACKGROUND_SERVICE_LOADER_H_
 #define MOJO_SERVICE_MANAGER_BACKGROUND_SERVICE_LOADER_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/threading/thread.h"
 #include "mojo/service_manager/service_loader.h"
 
 namespace mojo {
 
 class ServiceManager;
 
 // ServiceLoader implementation that creates a background thread and issues load
 // requests there.
 class MOJO_SERVICE_MANAGER_EXPORT BackgroundServiceLoader
     : public ServiceLoader {
  public:
   BackgroundServiceLoader(scoped_ptr<ServiceLoader> real_loader,
                           const char* thread_name,
                           base::MessageLoop::Type message_loop_type);
   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;
 
  private:
   class BackgroundLoader;
 
   // These functions are exected on the background thread. They call through
   // to |background_loader_| to do the actual loading.
   // TODO: having this code take a |manager| is fragile (as ServiceManager isn't
   // thread safe).
   void LoadServiceOnBackgroundThread(
       ServiceManager* manager,
       const GURL& url,
-      ScopedMessagePipeHandle* shell_handle);
+      ScopedMessagePipeHandle shell_handle);
   void OnServiceErrorOnBackgroundThread(ServiceManager* manager,
                                         const GURL& url);
   void ShutdownOnBackgroundThread();
 
   scoped_ptr<ServiceLoader> loader_;
   base::Thread thread_;
   base::MessageLoop::Type message_loop_type_;
 
   // Lives on |thread_|. Trivial interface that calls through to |loader_|.
   BackgroundLoader* background_loader_;
 
   DISALLOW_COPY_AND_ASSIGN(BackgroundServiceLoader);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_SERVICE_MANAGER_BACKGROUND_SERVICE_LOADER_H_