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

chrome/test/webdriver/webdriver_key_converter.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 "chrome/test/webdriver/webdriver_key_converter.h"
 
 #include "base/format_macros.h"
 #include "base/logging.h"
 #include "base/stringprintf.h"
 #include "base/utf_string_conversions.h"
@@ skipping 144 matching lines @@
   }
   *client_should_skip = should_skip;
   return true;
 }
 
 }  // namespace
 
 namespace webdriver {
 
 WebKeyEvent CreateKeyDownEvent(ui::KeyboardCode key_code, int modifiers) {
-  return WebKeyEvent(automation::kRawKeyDownType, key_code, "", "", modifiers);
+  return WebKeyEvent(automation::kRawKeyDownType,
+                     key_code,
+                     std::string(),
+                     std::string(),
+                     modifiers);
 }
 
 WebKeyEvent CreateKeyUpEvent(ui::KeyboardCode key_code, int modifiers) {
-  return WebKeyEvent(automation::kKeyUpType, key_code, "", "", modifiers);
+  return WebKeyEvent(automation::kKeyUpType,
+                     key_code,
+                     std::string(),
+                     std::string(),
+                     modifiers);
 }
 
 WebKeyEvent CreateCharEvent(const std::string& unmodified_text,
                             const std::string& modified_text,
                             int modifiers) {
   return WebKeyEvent(automation::kCharType,
                      ui::VKEY_UNKNOWN,
                      unmodified_text,
                      modified_text,
                      modifiers);
@@ skipping 138 matching lines @@
             CreateKeyUpEvent(kModifiers[i].key_code, sticky_modifiers));
       }
     }
   }
   client_key_events->swap(key_events);
   *modifiers = sticky_modifiers;
   return true;
 }
 
 }  // namespace webdriver