Use StringPiece for CreateUploader/NetMetricsLogUploader params.

chromecast/browser/metrics/cast_metrics_service_client.h

 // 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.
 
 #ifndef CHROMECAST_BROWSER_METRICS_CAST_METRICS_SERVICE_CLIENT_H_
 #define CHROMECAST_BROWSER_METRICS_CAST_METRICS_SERVICE_CLIENT_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 62 matching lines @@
   int32_t GetProduct() override;
   std::string GetApplicationLocale() override;
   bool GetBrand(std::string* brand_code) override;
   ::metrics::SystemProfileProto::Channel GetChannel() override;
   std::string GetVersionString() override;
   void InitializeSystemProfileMetrics(
       const base::Closure& done_callback) override;
   void CollectFinalMetricsForLog(const base::Closure& done_callback) override;
   std::string GetMetricsServerUrl() override;
   std::unique_ptr<::metrics::MetricsLogUploader> CreateUploader(
-      const std::string& server_url,
-      const std::string& mime_type,
+      base::StringPiece server_url,
+      base::StringPiece mime_type,
       ::metrics::MetricsLogUploader::MetricServiceType service_type,
       const base::Callback<void(int)>& on_upload_complete) override;
   base::TimeDelta GetStandardUploadInterval() override;
 
   // ::metrics::EnabledStateProvider:
   bool IsConsentGiven() override;
 
   // Starts/stops the metrics service.
   void EnableMetricsService(bool enabled);
 
@@ skipping 24 matching lines @@
   std::unique_ptr<::metrics::EnabledStateProvider> enabled_state_provider_;
   net::URLRequestContextGetter* const request_context_;
 
   DISALLOW_COPY_AND_ASSIGN(CastMetricsServiceClient);
 };
 
 }  // namespace metrics
 }  // namespace chromecast
 
 #endif  // CHROMECAST_BROWSER_METRICS_CAST_METRICS_SERVICE_CLIENT_H_