Basic UkmService implementation

blimp/engine/app/blimp_metrics_service_client.cc

Index: blimp/engine/app/blimp_metrics_service_client.cc
diff --git a/blimp/engine/app/blimp_metrics_service_client.cc b/blimp/engine/app/blimp_metrics_service_client.cc
index 94bad89691d6c784f077f5211ac2b733d203dab4..181eef0d0698a4b08d57ba25af8fa05d05ee7a95 100644
--- a/blimp/engine/app/blimp_metrics_service_client.cc
+++ b/blimp/engine/app/blimp_metrics_service_client.cc
@@ -139,11 +139,13 @@ void BlimpMetricsServiceClient::CollectFinalMetricsForLog(
 
 std::unique_ptr<metrics::MetricsLogUploader>
 BlimpMetricsServiceClient::CreateUploader(
+    const std::string& server_url,
+    const std::string& mime_type,
     const base::Callback<void(int)>& on_upload_complete) {
   return base::WrapUnique<metrics::MetricsLogUploader>(
       new metrics::NetMetricsLogUploader(
-          request_context_getter_.get(), metrics::kDefaultMetricsServerUrl,
-          metrics::kDefaultMetricsMimeType, on_upload_complete));
+          request_context_getter_.get(), server_url,
+          mime_type, on_upload_complete));
 }
 
 base::TimeDelta BlimpMetricsServiceClient::GetStandardUploadInterval() {