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

chrome/test/chromedriver/key_converter.cc

 // Copyright (c) 2013 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 "chrome/test/chromedriver/key_converter.h"
 
 #include "base/format_macros.h"
 #include "base/stringprintf.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/test/chromedriver/chrome/status.h"
@@ skipping 140 matching lines @@
   } else {
     return false;
   }
   *client_should_skip = should_skip;
   return true;
 }
 
 }  // namespace
 
 KeyEvent CreateKeyDownEvent(ui::KeyboardCode key_code, int modifiers) {
-  return KeyEvent(kRawKeyDownEventType, modifiers, "", "", key_code);
+  return KeyEvent(
+      kRawKeyDownEventType, modifiers, std::string(), std::string(), key_code);
 }
 
 KeyEvent CreateKeyUpEvent(ui::KeyboardCode key_code, int modifiers) {
-  return KeyEvent(kKeyUpEventType, modifiers, "", "", key_code);
+  return KeyEvent(
+      kKeyUpEventType, modifiers, std::string(), std::string(), key_code);
 }
 
 KeyEvent CreateCharEvent(const std::string& unmodified_text,
                          const std::string& modified_text,
                          int modifiers) {
   return KeyEvent(kCharEventType,
                   modifiers,
                   modified_text,
                   unmodified_text,
                   ui::VKEY_UNKNOWN);
@@ skipping 130 matching lines @@
       if (necessary_modifiers[i]) {
         key_events.push_back(
             CreateKeyUpEvent(kModifiers[i].key_code, sticky_modifiers));
       }
     }
   }
   client_key_events->swap(key_events);
   *modifiers = sticky_modifiers;
   return Status(kOk);
 }