media: Add ServiceFactory mojo interface and implementation.

media/mojo/services/mojo_cdm_service_context.h

 // Copyright 2015 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 MEDIA_MOJO_SERVICES_MOJO_CDM_SERVICE_CONTEXT_H_
 #define MEDIA_MOJO_SERVICES_MOJO_CDM_SERVICE_CONTEXT_H_
 
-#include "base/containers/scoped_ptr_hash_map.h"
+#include <map>
+
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "media/base/cdm_context.h"
 #include "media/base/media_export.h"
-#include "media/mojo/services/mojo_cdm_service.h"
 
 namespace media {
 
+class MojoCdmService;
+
 // A class that creates, owns and manages all MojoCdmService instances.
 class MEDIA_EXPORT MojoCdmServiceContext : public CdmContextProvider {
  public:
   MojoCdmServiceContext();
   ~MojoCdmServiceContext() override;
 
+  base::WeakPtr<MojoCdmServiceContext> GetWeakPtr();
+
   // Registers The |cdm_service| with |cdm_id|.
   void RegisterCdm(int cdm_id, MojoCdmService* cdm_service);
 
   // Unregisters the CDM. Must be called before the CDM is destroyed.
   void UnregisterCdm(int cdm_id);
 
   // CdmContextProvider implementation.
   // The returned CdmContext can be destroyed at any time if the pipe is
   // disconnected.
   // TODO(xhwang): When implementing SetCdm(), make sure we never dereference
   // garbage. For example, use media::PlayerTracker.
   CdmContext* GetCdmContext(int32_t cdm_id) override;
 
  private:
   // A map between CDM ID and MojoCdmService.
   std::map<int, MojoCdmService*> cdm_services_;
 
+  // NOTE: Weak pointers must be invalidated before all other member variables.
+  base::WeakPtrFactory<MojoCdmServiceContext> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(MojoCdmServiceContext);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_MOJO_SERVICES_MOJO_CDM_SERVICE_CONTEXT_H_