Use scroll-boundary-behavior to control overscroll-refresh/glow on android.

cc/input/scroll_boundary_behavior.h

 // 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_
 
 #include "cc/cc_export.h"
 
 namespace cc {
 
 struct CC_EXPORT ScrollBoundaryBehavior {
   enum ScrollBoundaryBehaviorType {
     // Same as contain but also hint that no overscroll affordance should be
     // triggered.
     kScrollBoundaryBehaviorTypeNone,
     // Allows the default behavior for the user agent.
     kScrollBoundaryBehaviorTypeAuto,
     // Hint to disable scroll chaining. The user agent may show an appropriate
     // overscroll affordance.
-    kScrollBoundaryBehaviorTypeContain
+    kScrollBoundaryBehaviorTypeContain,
+    kScrollBoundaryBehaviorTypeMax = kScrollBoundaryBehaviorTypeContain
   };
 
   ScrollBoundaryBehavior()
       : x(kScrollBoundaryBehaviorTypeAuto),
         y(kScrollBoundaryBehaviorTypeAuto) {}
   explicit ScrollBoundaryBehavior(ScrollBoundaryBehaviorType type)
       : x(type), y(type) {}
   ScrollBoundaryBehavior(ScrollBoundaryBehaviorType x_type,
                          ScrollBoundaryBehaviorType y_type)
       : x(x_type), y(y_type) {}
 
   ScrollBoundaryBehaviorType x;
   ScrollBoundaryBehaviorType y;
 
   bool operator==(const ScrollBoundaryBehavior& a) const {
     return (a.x == x) && (a.y == y);
   }
   bool operator!=(const ScrollBoundaryBehavior& a) const {
     return !(*this == a);
   }
 };
 
 }  // namespace cc
 
 #endif  // CC_INPUT_SCROLL_BOUNDARY_BEHAVIOR_H_