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

chrome/browser/password_manager/native_backend_kwallet_x_unittest.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 <algorithm>
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 297 matching lines @@
   EXPECT_TRUE(envs.empty());
   EXPECT_TRUE(startup_id.empty());
   EXPECT_FALSE(blind);
 
   if (kwallet_runnable_)
     kwallet_running_ = true;
 
   scoped_ptr<dbus::Response> response(dbus::Response::CreateEmpty());
   dbus::MessageWriter writer(response.get());
   writer.AppendInt32(klauncher_ret_);
-  writer.AppendString("");   // dbus_name
+  writer.AppendString(std::string());  // dbus_name
   writer.AppendString(klauncher_error_);
   writer.AppendInt32(1234);  // pid
   return response.release();
 }
 
 dbus::Response* NativeBackendKWalletTest::KWalletMethodCall(
     dbus::MethodCall* method_call, testing::Unused) {
   if (!kwallet_running_)
     return NULL;
   EXPECT_EQ("org.kde.KWallet", method_call->GetInterface());
@@ skipping 750 matching lines @@
   CheckVersion0Pickle(true, PasswordForm::SCHEME_BASIC);
 }
 
 TEST_F(NativeBackendKWalletPickleTest, ReadsOld64BitHTMLPickles) {
   CheckVersion0Pickle(false, PasswordForm::SCHEME_HTML);
 }
 
 TEST_F(NativeBackendKWalletPickleTest, ReadsOld64BitHTTPPickles) {
   CheckVersion0Pickle(false, PasswordForm::SCHEME_BASIC);
 }