[chromedriver] Implement commands: findChildElement, findChildElements.

chrome/test/chromedriver/status.h

 // 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.
 
 #ifndef CHROME_TEST_CHROMEDRIVER_STATUS_H_
 #define CHROME_TEST_CHROMEDRIVER_STATUS_H_
 
 #include <string>
 
 // WebDriver standard status codes.
 enum StatusCode {
   kOk = 0,
   kNoSuchElement = 7,
   kUnknownCommand = 9,
+  kStaleElementReference = 10,
   kUnknownError = 13,
   kXPathLookupError = 19,
   kInvalidSelector = 32,
   kSessionNotCreatedException = 33,
   // Chrome-specific status codes.
   kNoSuchSession = 100,
   kChromeNotReachable,
 };
 
 // Represents a WebDriver status, which may be an error or ok.
@@ skipping 11 matching lines @@
   StatusCode code() const;
 
   const std::string& message() const;
 
  private:
   StatusCode code_;
   std::string msg_;
 };
 
 #endif  // CHROME_TEST_CHROMEDRIVER_STATUS_H_