Rewrite std::string("") to std::string(), Linux edition.

chrome/test/perf/rendering/throughput_tests.cc

Index: chrome/test/perf/rendering/throughput_tests.cc
diff --git a/chrome/test/perf/rendering/throughput_tests.cc b/chrome/test/perf/rendering/throughput_tests.cc
index 79d6bbb32030d2f6f1916e04ca2649f4619cc58a..08a1483e0dd00fff371e5fd9b34e546186b40e6d 100644
--- a/chrome/test/perf/rendering/throughput_tests.cc
+++ b/chrome/test/perf/rendering/throughput_tests.cc
@@ -383,8 +383,12 @@ class ThroughputTest : public BrowserPerfTest {
                              ran_on_gpu ? "gpu" : "software";
     std::string mean_and_error = base::StringPrintf("%f,%f", mean_ms,
                                                     std_dev_ms);
-    perf_test::PrintResultMeanAndError(test_name, "", trace_name,
-                                       mean_and_error, "frame_time", true);
+    perf_test::PrintResultMeanAndError(test_name,
+                                       std::string(),
+                                       trace_name,
+                                       mean_and_error,
+                                       "frame_time",
+                                       true);
 
     if (flags & kAllowExternalDNS)
       ResetAllowExternalDNS();