WIP - compositor worker mega patch.

third_party/WebKit/public/platform/WebCompositorMutableStateProvider.h

-// Copyright 2015 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 WebCompositorMutableStateProvider_h
-#define WebCompositorMutableStateProvider_h
-
-#include "public/platform/WebPassOwnPtr.h"
-
-#include <cstdint>
-
-namespace blink {
-
-class WebCompositorMutableState;
-
-// This class is a window onto compositor-owned state. It vends out wrappers
-// around per-element bits of this state.
-class WebCompositorMutableStateProvider {
-public:
-    virtual ~WebCompositorMutableStateProvider() { }
-
-    // The caller is expected to take ownership.
-    virtual WebPassOwnPtr<WebCompositorMutableState> getMutableStateFor(uint64_t elementId) = 0;
-};
-
-} // namespace blink
-
-#endif // WebCompositorMutableStateProvider_h