[Sync] Services can now always assume processor exists.

components/sync/core/shared_model_type_processor.cc

Index: components/sync/core/shared_model_type_processor.cc
diff --git a/components/sync/core/shared_model_type_processor.cc b/components/sync/core/shared_model_type_processor.cc
index 4822e6e591e7b96a135df496e082a4ce62036e13..fc1b76491334762ffb4daac8fb42671bf5546d4d 100644
--- a/components/sync/core/shared_model_type_processor.cc
+++ b/components/sync/core/shared_model_type_processor.cc
@@ -38,8 +38,7 @@ SharedModelTypeProcessor::~SharedModelTypeProcessor() {}
 std::unique_ptr<ModelTypeChangeProcessor>
 SharedModelTypeProcessor::CreateAsChangeProcessor(ModelType type,
                                                   ModelTypeService* service) {
-  return std::unique_ptr<ModelTypeChangeProcessor>(
-      new SharedModelTypeProcessor(type, service));
+  return base::MakeUnique<SharedModelTypeProcessor>(type, service);
 }
 
 void SharedModelTypeProcessor::OnSyncStarting(
@@ -115,7 +114,7 @@ void SharedModelTypeProcessor::ConnectIfReady() {
   std::unique_ptr<ActivationContext> activation_context;
 
   if (!start_error_.IsSet()) {
-    activation_context = base::WrapUnique(new ActivationContext);
+    activation_context = base::MakeUnique<ActivationContext>();
     activation_context->model_type_state = model_type_state_;
     activation_context->type_processor =
         base::MakeUnique<ModelTypeProcessorProxy>(
@@ -170,6 +169,10 @@ void SharedModelTypeProcessor::DisableSync() {
   service_->ApplySyncChanges(std::move(change_list), EntityChangeList());
 }
 
+bool SharedModelTypeProcessor::IsTrackingMetadata() {
+  return model_type_state_.initial_sync_done();
+}
+
 SyncError SharedModelTypeProcessor::CreateAndUploadError(
     const tracked_objects::Location& location,
     const std::string& message) {