Add support for new scroll valuators coming from CMT

ui/base/events.h

Index: ui/base/events.h
diff --git a/ui/base/events.h b/ui/base/events.h
index 69f83084f76831a6cf9ec589ea6efc7ef428f612..aab93664b494c1a7d8a10e2d3ed05f691e366433 100644
--- a/ui/base/events.h
+++ b/ui/base/events.h
@@ -35,6 +35,7 @@ enum EventType {
   ET_TOUCH_CANCELLED,
   ET_DROP_TARGET_EVENT,
   ET_FOCUS_CHANGE,
+  ET_SCROLL,
 };
 
 // Event flags currently supported
@@ -70,6 +71,9 @@ enum TouchStatus {
                              // unused touch event was handled.
 };
 
+// Updates the list of devices for cached properties.
+UI_EXPORT void UpdateDeviceList();
+
 // Get the EventType from a native event.
 UI_EXPORT EventType EventTypeFromNative(const base::NativeEvent& native_event);
 
@@ -111,6 +115,12 @@ UI_EXPORT float GetTouchAngle(const base::NativeEvent& native_event);
 // Gets the force from a native_event. Normalized to be [0, 1]. Default is 0.0.
 UI_EXPORT float GetTouchForce(const base::NativeEvent& native_event);
 
+// Returns whether this is a scroll event and optionally gets the amount to be
+// scrolled. |x_offset| and |y_offset| can be NULL.
+UI_EXPORT bool GetScrollOffsets(const base::NativeEvent& native_event,
+                                float* x_offset,
+                                float* y_offset);
+
 // Creates and returns no-op event.
 UI_EXPORT base::NativeEvent CreateNoopEvent();