Adding momentum/overscroll to views:: ScrollViews

ui/events/event_constants.h

 // Copyright (c) 2012 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 UI_EVENTS_EVENT_CONSTANTS_H_
 #define UI_EVENTS_EVENT_CONSTANTS_H_
 
 namespace ui {
 
 // Event types. (prefixed because of a conflict with windows headers)
@@ skipping 142 matching lines @@
 
 // Phase of the event dispatch.
 enum EventPhase {
   EP_PREDISPATCH,
   EP_PRETARGET,
   EP_TARGET,
   EP_POSTTARGET,
   EP_POSTDISPATCH
 };
 
+enum EventMomentumPhase {
+  // Event stream can not result in momentum, or is a non-momentum update to an
+  // event stream already begun.
+  EM_PHASE_NONE = 0,
+
+  // Event is the beginning of an event stream that may result in momentum.
+  EM_PHASE_MAY_BEGIN = 0x1,
+
+  // Event is an update while in a momentum phase.
+  EM_PHASE_INERTIAL_UPDATE = 0x2,
+
+  // Event marks the end of the current event stream.
+  EM_PHASE_END = 0x4,
+};
+
 // Device ID for Touch and Key Events.
 enum EventDeviceId {
   ED_UNKNOWN_DEVICE = -1
 };
 
 // Pointing device type.
 enum class EventPointerType : int {
   POINTER_TYPE_UNKNOWN = 0,
   POINTER_TYPE_MOUSE,
   POINTER_TYPE_PEN,
   POINTER_TYPE_TOUCH,
 };
 
 // Device type for gesture events.
 enum class GestureDeviceType : int {
   DEVICE_UNKNOWN = 0,
   DEVICE_TOUCHPAD,
   DEVICE_TOUCHSCREEN,
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_EVENT_CONSTANTS_H_