Use StringPiece for CreateUploader/NetMetricsLogUploader params.

android_webview/native/aw_metrics_service_client_impl.cc

Index: android_webview/native/aw_metrics_service_client_impl.cc
diff --git a/android_webview/native/aw_metrics_service_client_impl.cc b/android_webview/native/aw_metrics_service_client_impl.cc
index d1ab432a32e5bf369f02631273baf45fbe475704..8b711b1c991f103c122ab05a3c2dbcd29bcde55f 100644
--- a/android_webview/native/aw_metrics_service_client_impl.cc
+++ b/android_webview/native/aw_metrics_service_client_impl.cc
@@ -203,8 +203,8 @@ void AwMetricsServiceClientImpl::CollectFinalMetricsForLog(
 
 std::unique_ptr<metrics::MetricsLogUploader>
 AwMetricsServiceClientImpl::CreateUploader(
-    const std::string& server_url,
-    const std::string& mime_type,
+    const base::StringPiece& server_url,
+    const base::StringPiece& mime_type,
     metrics::MetricsLogUploader::MetricServiceType service_type,
     const base::Callback<void(int)>& on_upload_complete) {
   return std::unique_ptr<::metrics::MetricsLogUploader>(