Make MetricsService upload logs through an interface.

components/metrics/test_metrics_service_client.cc

 // Copyright 2014 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 "components/metrics/test_metrics_service_client.h"
 
 #include "base/callback.h"
 
 namespace metrics {
 
@@ skipping 37 matching lines @@
 void TestMetricsServiceClient::StartGatheringMetrics(
     const base::Closure& done_callback) {
   done_callback.Run();
 }
 
 void TestMetricsServiceClient::CollectFinalMetrics(
     const base::Closure& done_callback) {
   done_callback.Run();
 }
 
+scoped_ptr<MetricsLogUploader> TestMetricsServiceClient::CreateUploader(
+    const std::string& server_url,
+    const std::string& mime_type,
+    const base::Callback<void(int)> on_upload_complete) {
+  return scoped_ptr<MetricsLogUploader>();
+}
+
 }  // namespace metrics