compositor-worker: plumb element id and mutable properties

third_party/WebKit/public/platform/WebCompositorMutableProperties.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 WebCompositorMutableProperties_h
+#define WebCompositorMutableProperties_h
+
+namespace blink {
+
+// TODO(vollick): we should not need a parallel enum.

[chrishtr, 2015/11/24 16:22:50]

Add a note that this has to be kept in sync with the other enum.

[Ian Vollick, 2015/11/25 18:28:45]

Done.

+enum WebCompositorMutableProperty {
+    WebCompositorMutablePropertyNone = 0,
+    WebCompositorMutablePropertyOpacity = 1 << 0,
+    WebCompositorMutablePropertyScrollLeft = 1 << 1,
+    WebCompositorMutablePropertyScrollTop = 1 << 2,
+    WebCompositorMutablePropertyTransform = 1 << 3,
+};
+
+const int kNumWebCompositorMutableProperties = 4;
+
+} // namespace blink
+
+#endif // WebCompositorMutableProperties_h