Cleanup: Remove unneeded forward declarations from various chrome subdirectories.

chrome/test/webdriver/commands/webdriver_command.h

 // Copyright (c) 2011 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.
 
 #ifndef CHROME_TEST_WEBDRIVER_COMMANDS_WEBDRIVER_COMMAND_H_
 #define CHROME_TEST_WEBDRIVER_COMMANDS_WEBDRIVER_COMMAND_H_
 
 #include <string>
 #include <vector>
 
 #include "chrome/test/webdriver/commands/command.h"
 
 namespace base {
 class DictionaryValue;
 }
 
 namespace webdriver {
 
-class Error;
 class Response;
 class Session;
 
 // All URLs that are found in the document:
 // http://code.google.com/p/selenium/wiki/JsonWireProtocol
 // and are to be supported for all browsers and platforms should inhert
 // this class.  For cases which do not invlove interaction with the
 // browser, such a transfering a file, inhert from the Command class
 // directly.
 class WebDriverCommand : public Command {
@@ skipping 10 matching lines @@
  protected:
   Session* session_;
   std::string session_id_;
 
   DISALLOW_COPY_AND_ASSIGN(WebDriverCommand);
 };
 
 }  // namespace webdriver
 
 #endif  // CHROME_TEST_WEBDRIVER_COMMANDS_WEBDRIVER_COMMAND_H_