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

chrome/test/perf/indexeddb_uitest.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/files/file_path.h"
 #include "base/path_service.h"
 #include "base/test/test_timeouts.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/common/automation_constants.h"
 #include "chrome/common/chrome_paths.h"
@@ skipping 45 matching lines @@
     return test_dir.AppendASCII("indexeddb");
   }
 
   bool WaitUntilTestCompletes(TabProxy* tab, const GURL& test_url) {
     return WaitUntilCookieValue(tab, test_url, "__done",
                                 TestTimeouts::large_test_timeout(), "1");
   }
 
   bool GetResults(TabProxy* tab, ResultsMap* results) {
     std::wstring json_wide;
-    bool succeeded = tab->ExecuteAndExtractString(L"",
+    bool succeeded = tab->ExecuteAndExtractString(
+        std::wstring(),
         L"window.domAutomationController.send("
         L"    JSON.stringify(automation.getResults()));",
         &json_wide);
 
     EXPECT_TRUE(succeeded);
     if (!succeeded)
       return false;
 
     std::string json = WideToUTF8(json_wide);
     return JsonDictionaryToMap(json, results);
   }
 
   void PrintResults(TabProxy* tab) {
     ResultsMap results;
     ASSERT_TRUE(GetResults(tab, &results));
 
     std::string trace_name = reference_ ? "t_ref" : "t";
 
     ResultsMap::const_iterator it = results.begin();
     for (; it != results.end(); ++it)
-      perf_test::PrintResultList(it->first, "", trace_name, it->second, "ms",
-                                 false);
+      perf_test::PrintResultList(
+          it->first, std::string(), trace_name, it->second, "ms", false);
   }
 
   DISALLOW_COPY_AND_ASSIGN(IndexedDBTest);
 };
 
 class IndexedDBReferenceTest : public IndexedDBTest {
  public:
   IndexedDBReferenceTest() : IndexedDBTest() {
     reference_ = true;
   }
 
   virtual void SetUp() {
     UseReferenceBuild();
     IndexedDBTest::SetUp();
   }
 };
 
 TEST_F(IndexedDBTest, Perf) {
 
   RunTest();
 }
 
 TEST_F(IndexedDBReferenceTest, Perf) {
 
   RunTest();
 }
 
 }  // namespace