Use element id's for animations

third_party/WebKit/Source/platform/graphics/CompositorElementId.h

Index: third_party/WebKit/Source/platform/graphics/CompositorElementId.h
diff --git a/third_party/WebKit/Source/platform/graphics/CompositorElementId.h b/third_party/WebKit/Source/platform/graphics/CompositorElementId.h
new file mode 100644
index 0000000000000000000000000000000000000000..df97665b7a136c80c564d7c700ee7beba96128f0
--- /dev/null
+++ b/third_party/WebKit/Source/platform/graphics/CompositorElementId.h
@@ -0,0 +1,25 @@
+// 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 {
+
+enum class CompositorSubElementId {
+    Primary = 1,

[jbroman, 2016/06/06 14:23:20]

nit: Any reason to assign these explicit values, instead of letting the compiler
assign them? Letting the compiler do it makes the diff smaller if one is ever
removed.

[Ian Vollick, 2016/06/06 16:31:29]

No reason. Removed.

+    Scroll = 2,
+    LinkHighlight = 3
+};
+
+using CompositorElementId = cc::ElementId;
+
+CompositorElementId PLATFORM_EXPORT createCompositorElementId(int domNodeId, CompositorSubElementId);
+
+} // namespace blink
+
+#endif // CompositorElementId_h