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

chrome/test/perf/rendering/latency_tests.cc

Index: chrome/test/perf/rendering/latency_tests.cc
diff --git a/chrome/test/perf/rendering/latency_tests.cc b/chrome/test/perf/rendering/latency_tests.cc
index 70939fd2755878b90f6cfbe257d400f8b64714e3..fdd00d77ecae94a7e0c32b10fede9f143a980704 100644
--- a/chrome/test/perf/rendering/latency_tests.cc
+++ b/chrome/test/perf/rendering/latency_tests.cc
@@ -153,7 +153,7 @@ class LatencyTest
         return "software";
       default:
         NOTREACHED() << "invalid mode";
-        return "";
+        return std::string();
     }
   }
 
@@ -586,8 +586,12 @@ double LatencyTest::CalculateLatency() {
   std::string trace_name = GetTraceName(test_flags_);
   std::string mean_and_error = base::StringPrintf("%f,%f", mean_latency,
                                                   mean_error);
-  perf_test::PrintResultMeanAndError(GetModeString(), "", trace_name,
-                                     mean_and_error, "frames", true);
+  perf_test::PrintResultMeanAndError(GetModeString(),
+                                     std::string(),
+                                     trace_name,
+                                     mean_and_error,
+                                     "frames",
+                                     true);
   return mean_latency;
 }