media: Add ServiceFactory mojo interface and implementation.

media/mojo/services/mojo_cdm_service_context.h

Index: media/mojo/services/mojo_cdm_service_context.h
diff --git a/media/mojo/services/mojo_cdm_service_context.h b/media/mojo/services/mojo_cdm_service_context.h
index dc55ad312c7b9d42e5f4523e27fd0c4255d7fddf..f3c2caf233164ff6e9962a43957768d55d1b3312 100644
--- a/media/mojo/services/mojo_cdm_service_context.h
+++ b/media/mojo/services/mojo_cdm_service_context.h
@@ -5,20 +5,25 @@
 #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);
 
@@ -36,6 +41,9 @@ class MEDIA_EXPORT MojoCdmServiceContext : public CdmContextProvider {
   // 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);
 };