In chromedriver, add /log handler

chrome/test/webdriver/webdriver_logging.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_WEBDRIVER_LOGGING_H_
+#define CHROME_TEST_WEBDRIVER_WEBDRIVER_LOGGING_H_
+
+#include <string>
+
+namespace webdriver {
+
+// Initializes logging for WebDriver. All logging below the given level
+// will be discarded.
+void InitWebDriverLogging(int min_log_level);
+
+// Retrieves the current contents of the WebDriver log file.
+// Returns true on success.
+bool GetLogContents(std::string* log_contents);
+
+}  // namespace webdriver
+
+#endif  // CHROME_TEST_WEBDRIVER_WEBDRIVER_LOGGING_H_