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

chrome/test/perf/rendering/throughput_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/files/file_path.h"
 #include "base/json/json_reader.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/path_service.h"
@@ skipping 365 matching lines @@
     ASSERT_TRUE(GetRateStats(rate_events, &stats, NULL));
     LOG(INFO) << "FPS = " << 1000000.0 / stats.mean_us;
 
     // Print perf results.
     double mean_ms = stats.mean_us / 1000.0;
     double std_dev_ms = stats.standard_deviation_us / 1000.0 / 1000.0;
     std::string trace_name = use_compositor_thread_? "gpu_thread" :
                              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();
 
     // Close the tab so that we can quit without timing out during the
     // wait-for-idle stage in browser_test framework.
     browser()->tab_strip_model()->GetActiveWebContents()->Close();
   }
 
  private:
@@ skipping 190 matching lines @@
 
 IN_PROC_BROWSER_TEST_F(ThroughputTestGPU, CanvasManyImagesGPU) {
   RunCanvasBenchTest("many_images", kNone | kIsGpuCanvasTest);
 }
 
 IN_PROC_BROWSER_TEST_F(ThroughputTestThread, CanvasManyImagesGPU) {
   RunCanvasBenchTest("many_images", kNone | kIsGpuCanvasTest);
 }
 
 }  // namespace