Define contentsProperties on ObjectPaintProperties, for use in paint invalidation.

third_party/WebKit/Source/core/paint/ObjectPaintProperties.cpp

+// 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.
+
+#include "core/paint/ObjectPaintProperties.h"
+
+namespace blink {
+
+void ObjectPaintProperties::getContentsProperties(PropertyTreeState& properties) const
+{
+    properties = localBorderBoxProperties()->propertyTreeState;
+    if (scrollTranslation())
+        properties.transform = scrollTranslation();
+    else if (svgLocalToBorderBoxTransform())
+        properties.transform = svgLocalToBorderBoxTransform();
+
+    if (overflowClip())
+        properties.clip = overflowClip();
+    else if (cssClip())
+        properties.clip = cssClip();
+    // TODO(chrishtr): cssClipFixedPosition needs to be handled somehow.
+}
+
+} // namespace blink