Use element id's for animations

third_party/WebKit/Source/platform/graphics/CompositorElementId.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 CompositorElementId_h
+#define CompositorElementId_h
+
+#include "cc/animation/element_id.h"
+#include "platform/PlatformExport.h"
+
+namespace blink {
+
+struct PLATFORM_EXPORT CompositorSubElementId {
+    enum class Value {
+        Scroll = 1,
+        ViewportScroll = 2,
+        LinkHighlight = 3
+    };
+};
+
+using CompositorElementId = cc::ElementId;
+
+CompositorElementId PLATFORM_EXPORT createCompositorElementId(int domNodeId, CompositorSubElementId::Value);
+
+} // namespace blink
+
+#endif // CompositorElementId_h