cc: Remove cc::settings, move them to LayerTreeSettings.

cc/test/test_common.h

-// Copyright 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 CC_TEST_TEST_COMMON_H_
-#define CC_TEST_TEST_COMMON_H_
-
-#include "cc/settings.h"
-
-namespace WebKitTests {
-
-// If you have a test that modifies or uses global settings, keep an instance
-// of this class to ensure that you start and end with a clean slate.
-class ScopedSettings {
-public:
-    ScopedSettings() { cc::Settings::resetForTest(); }
-    ~ScopedSettings() { cc::Settings::resetForTest(); }
-};
-
-} // namespace WebKitTests
-
-#endif  // CC_TEST_TEST_COMMON_H_