Add initial CC support for scroll-blocks-on

cc/layers/scroll_blocks_on.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 CC_LAYERS_SCROLL_BLOCKS_ON_H_
+#define CC_LAYERS_SCROLL_BLOCKS_ON_H_
+
+enum ScrollBlocksOn {
+  ScrollBlocksOnNone = 0x0,
+  ScrollBlocksOnStartTouch = 0x1,
+  ScrollBlocksOnWheelEvent = 0x2,
+  ScrollBlocksOnScrollEvent = 0x4,
+  ScrollBlocksOnMax = ScrollBlocksOnStartTouch | ScrollBlocksOnWheelEvent |
+                      ScrollBlocksOnScrollEvent
+};
+
+inline ScrollBlocksOn operator|(ScrollBlocksOn a, ScrollBlocksOn b) {
+  return ScrollBlocksOn(static_cast<int>(a) | static_cast<int>(b));
+}
+
+inline ScrollBlocksOn& operator|=(ScrollBlocksOn& a, ScrollBlocksOn b) {
+  return a = a | b;
+}
+
+#endif  // CC_LAYERS_SCROLL_BLOCKS_ON_H_