[content shell] move code common to several processes to a common dir

content/shell/common/webkit_test_helpers.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 CONTENT_SHELL_WEBKIT_TEST_HELPERS_H_
-#define CONTENT_SHELL_WEBKIT_TEST_HELPERS_H_
+#ifndef CONTENT_SHELL_COMMON_WEBKIT_TEST_HELPERS_H_
+#define CONTENT_SHELL_COMMON_WEBKIT_TEST_HELPERS_H_
 
 struct WebPreferences;
 
 namespace WebTestRunner {
 struct WebPreferences;
 }
 
 namespace base {
 class FilePath;
 }
@@ skipping 13 matching lines @@
 void ApplyLayoutTestDefaultPreferences(WebPreferences* prefs);
 
 // Returns the root of the Blink checkout.
 base::FilePath GetWebKitRootDirFilePath();
 
 // Returns the root of the chromium checkout.
 base::FilePath GetChromiumRootDirFilePath();
 
 }  // namespace content
 
-#endif  // CONTENT_SHELL_WEBKIT_TEST_HELPERS_H_
+#endif  // CONTENT_SHELL_COMMON_WEBKIT_TEST_HELPERS_H_