Split testing_pref_service.h/.cc into two parts, generic vs. Chrome-specific.

chrome/test/base/scoped_testing_local_state.h

+// Copyright (c) 2013 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_BASE_SCOPED_TESTING_LOCAL_STATE_H_
+#define CHROME_TEST_BASE_SCOPED_TESTING_LOCAL_STATE_H_
+
+#include "base/basictypes.h"
+#include "chrome/test/base/testing_pref_service.h"
+
+class TestingBrowserProcess;
+
+// Helper class to temporarily set up a |local_state| in the global
+// TestingBrowserProcess (for most unit tests it's NULL).
+class ScopedTestingLocalState {
+ public:
+  explicit ScopedTestingLocalState(TestingBrowserProcess* browser_process);
+  ~ScopedTestingLocalState();
+
+  TestingPrefServiceSimple* Get() {
+    return &local_state_;
+  }
+
+ private:
+  TestingBrowserProcess* browser_process_;
+  TestingPrefServiceSimple local_state_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedTestingLocalState);
+};
+
+#endif  // CHROME_TEST_BASE_SCOPED_TESTING_LOCAL_STATE_H_