media: Add ServiceFactory mojo interface and implementation.

media/mojo/services/mojo_cdm_service_context.cc

 // 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.
 
 #include "media/mojo/services/mojo_cdm_service_context.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
+#include "media/mojo/services/mojo_cdm_service.h"
 
 namespace media {
 
-MojoCdmServiceContext::MojoCdmServiceContext() {
+MojoCdmServiceContext::MojoCdmServiceContext() : weak_ptr_factory_(this) {}
+
+MojoCdmServiceContext::~MojoCdmServiceContext() {
 }
 
-MojoCdmServiceContext::~MojoCdmServiceContext() {
+base::WeakPtr<MojoCdmServiceContext> MojoCdmServiceContext::GetWeakPtr() {
+  return weak_ptr_factory_.GetWeakPtr();
 }
 
 void MojoCdmServiceContext::RegisterCdm(int cdm_id,
                                         MojoCdmService* cdm_service) {
   DCHECK(!cdm_services_.count(cdm_id));
   DCHECK(cdm_service);
   cdm_services_[cdm_id] = cdm_service;
 }
 
 void MojoCdmServiceContext::UnregisterCdm(int cdm_id) {
   DCHECK(cdm_services_.count(cdm_id));
   cdm_services_.erase(cdm_id);
 }
 
 CdmContext* MojoCdmServiceContext::GetCdmContext(int32_t cdm_id) {
   auto cdm_service = cdm_services_.find(cdm_id);
   if (cdm_service == cdm_services_.end()) {
     LOG(ERROR) << "CDM context not found: " << cdm_id;
     return nullptr;
   }
 
   return cdm_service->second->GetCdmContext();
 }
 
 }  // namespace media