Implement CSS: scroll-boundary-behavior

cc/input/scroll_boundary_behavior.h

Index: cc/input/scroll_boundary_behavior.h
diff --git a/cc/input/scroll_boundary_behavior.h b/cc/input/scroll_boundary_behavior.h
new file mode 100644
index 0000000000000000000000000000000000000000..ae7decf796f00df7d32492516643c1adfe4d6b91
--- /dev/null
+++ b/cc/input/scroll_boundary_behavior.h
@@ -0,0 +1,20 @@
+// Copyright (c) 2017 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 CC_INPUT_SCROLL_BOUNDARY_BEHAVIOR_H_
+#define CC_INPUT_SCROLL_BOUNDARY_BEHAVIOR_H_
+
+namespace cc {
+
+enum ScrollBoundaryBehavior {
+  SCROLL_BOUNDARY_BEHAVIOR_PROPAGATE,
+
+  SCROLL_BOUNDARY_BEHAVIOR_CONTAIN,
+
+  SCROLL_BOUNDARY_BEHAVIOR_NONE
+};
+
+}  // namespace cc
+
+#endif  // CC_INPUT_SCROLL_BOUNDARY_BEHAVIOR_H_