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

chrome/test/ppapi/ppapi_test.cc

Index: chrome/test/ppapi/ppapi_test.cc
diff --git a/chrome/test/ppapi/ppapi_test.cc b/chrome/test/ppapi/ppapi_test.cc
index bec32a6bb0cdad62736243337dd080158318d6a0..4cc99f48e95665b48895138719c4a69baff0c5ff 100644
--- a/chrome/test/ppapi/ppapi_test.cc
+++ b/chrome/test/ppapi/ppapi_test.cc
@@ -156,7 +156,7 @@ GURL PPAPITestBase::GetTestFileUrl(const std::string& test_case) {
   GURL test_url = net::FilePathToFileURL(test_path);
 
   GURL::Replacements replacements;
-  std::string query = BuildQuery("", test_case);
+  std::string query = BuildQuery(std::string(), test_case);
   replacements.SetQuery(query.c_str(), url_parse::Component(0, query.size()));
   return test_url.ReplaceComponents(replacements);
 }
@@ -182,7 +182,7 @@ void PPAPITestBase::RunTestViaHTTP(const std::string& test_case) {
                               net::TestServer::kLocalhost,
                               document_root);
   ASSERT_TRUE(http_server.Start());
-  RunTestURL(GetTestURL(http_server, test_case, ""));
+  RunTestURL(GetTestURL(http_server, test_case, std::string()));
 }
 
 void PPAPITestBase::RunTestWithSSLServer(const std::string& test_case) {