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

content/public/test/test_launcher.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 "content/public/test/test_launcher.h"
 
 #include <string>
 #include <vector>
 
 #include "base/command_line.h"
@@ skipping 436 matching lines @@
 
   DCHECK(!command_line->HasSwitch(kGTestListTestsFlag));
 
   testing::UnitTest* const unit_test = testing::UnitTest::GetInstance();
 
   std::string filter = command_line->GetSwitchValueASCII(kGTestFilterFlag);
 
   // Split --gtest_filter at '-', if there is one, to separate into
   // positive filter and negative filter portions.
   std::string positive_filter = filter;
-  std::string negative_filter = "";
+  std::string negative_filter;
   size_t dash_pos = filter.find('-');
   if (dash_pos != std::string::npos) {
     positive_filter = filter.substr(0, dash_pos);  // Everything up to the dash.
     negative_filter = filter.substr(dash_pos + 1); // Everything after the dash.
   }
 
   int num_runnable_tests = 0;
   int test_run_count = 0;
   int timeout_count = 0;
   std::vector<std::string> failed_tests;
@@ skipping 276 matching lines @@
       cycles--;
   }
   return exit_code;
 }
 
 TestLauncherDelegate* GetCurrentTestLauncherDelegate() {
   return g_launcher_delegate;
 }
 
 }  // namespace content