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

content/shell/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_
-
-struct WebPreferences;
-
-namespace WebTestRunner {
-struct WebPreferences;
-}
-
-namespace base {
-class FilePath;
-}
-
-struct WebPreferences;
-
-namespace content {
-
-// The TestRunner library keeps its settings in a WebTestRunner::WebPreferenes
-// object. The content_shell, however, uses WebPreferences. This
-// method exports the settings from the WebTestRunner library which are relevant
-// for layout tests.
-void ExportLayoutTestSpecificPreferences(
-    const WebTestRunner::WebPreferences& from, WebPreferences* to);
-
-// Applies settings that differ between layout tests and regular mode.
-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_