Expose scroll customization for touch to JS (behind REF).

Source/core/page/scrolling/NativeScrollBehavior.h

Index: Source/core/page/scrolling/NativeScrollBehavior.h
diff --git a/Source/core/page/scrolling/NativeScrollBehavior.h b/Source/core/page/scrolling/NativeScrollBehavior.h
new file mode 100644
index 0000000000000000000000000000000000000000..9518d2a673b96e38055422bad9658472a94e3ea0
--- /dev/null
+++ b/Source/core/page/scrolling/NativeScrollBehavior.h
@@ -0,0 +1,18 @@
+// 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 NativeScrollBehavior_h
+#define NativeScrollBehavior_h
+
+namespace blink {
+
+enum class NativeScrollBehavior {
+    DisableNativeScroll,
+    PerformBeforeNativeScroll,
+    PerformAfterNativeScroll,
+};
+
+} // namespace blink
+
+#endif // NativeScrollBehavior_h