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

chrome/test/perf/rendering/latency_tests.cc

 // Copyright (c) 2012 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 "base/command_line.h"
 #include "base/file_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/path_service.h"
 #include "base/stringprintf.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 135 matching lines @@
   std::string GetModeString() {
     switch (mode_) {
       case kWebGL:
         return "webgl";
       case kWebGLThread:
         return "webgl_thread";
       case kSoftware:
         return "software";
       default:
         NOTREACHED() << "invalid mode";
-        return "";
+        return std::string();
     }
   }
 
   std::string GetTraceName(int flags);
 
   std::string GetUrlModeString(int flags);
 
   std::string GetUrl(int flags);
 
   void GetMeanFrameTimeMicros(int* frame_time) const;
@@ skipping 412 matching lines @@
 
   double mean_error = 0.0;
   for (size_t i = 0; i < num_consider; ++i) {
     double offset = fabs(mean_latency - latencies[i]);
     mean_error = (offset > mean_error) ? offset : mean_error;
   }
 
   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;
 }
 
 std::string LatencyTest::GetTraceName(int flags) {
   if (flags == 0)
     return "simple";
   std::string name;
   if (flags & kInputHeavy)
     name += "ih";
   if (flags & kInputDirty)
@@ skipping 143 matching lines @@
     kInputHeavy | kInputDirty | kRafHeavy, \
     kInputHeavy | kInputDirty | kRafHeavy | kPaintHeavy, \
     kInputDirty | kPaintHeavy, \
     kInputDirty | kRafHeavy | kPaintHeavy)
 
 INSTANTIATE_TEST_CASE_P(, LatencyTestWebGL, LATENCY_SUITE_MODES());
 INSTANTIATE_TEST_CASE_P(, LatencyTestWebGLThread, LATENCY_SUITE_MODES());
 INSTANTIATE_TEST_CASE_P(, LatencyTestSW, LATENCY_SUITE_MODES());
 
 }  // namespace