compositor-worker: cc->blink mutation plumbing

third_party/WebKit/public/platform/WebCompositorMutations.h

+// Copyright 2016 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 WebCompositorMutations_h
+#define WebCompositorMutations_h
+
+#include "cc/animation/layer_tree_mutations.h"
+
+namespace blink {
+
+// This class contains the mutation data to be plumbed back to the main thread
+// after a CompositorWorker callback runs. It is a do-nothing base class since
+// these mutations are only used within blink.
+struct WebCompositorMutations : public cc::LayerTreeMutations {
+    virtual ~WebCompositorMutations() {}
+};
+
+} // namespace blink
+
+#endif // WebCompositorMutations_h