Postpone rail application for touch scrolling - chrome side.

ui/events/gesture_event_details.h

Index: ui/events/gesture_event_details.h
diff --git a/ui/events/gesture_event_details.h b/ui/events/gesture_event_details.h
index 502df8abdf6d13a92033ee9f931eaca9a32f2cc7..f02b0722969f44a030d7535cb5f4c967e102d359 100644
--- a/ui/events/gesture_event_details.h
+++ b/ui/events/gesture_event_details.h
@@ -15,8 +15,14 @@ namespace ui {
 
 struct EVENTS_BASE_EXPORT GestureEventDetails {
  public:
+  enum class ScrollRailState { Vertical, Horizontal, Free };
+
   GestureEventDetails();
   explicit GestureEventDetails(EventType type);
+  GestureEventDetails(EventType type,
+                      float delta_x,
+                      float delta_y,
+                      ScrollRailState scroll_rail_state);
   GestureEventDetails(EventType type, float delta_x, float delta_y);
 
   // The caller is responsible for ensuring that the gesture data from |other|
@@ -70,12 +76,24 @@ struct EVENTS_BASE_EXPORT GestureEventDetails {
 
   float velocity_x() const {
     DCHECK_EQ(ET_SCROLL_FLING_START, type_);
-    return data_.fling_velocity.x;
+    return data_.fling_start.x;
   }
 
   float velocity_y() const {
     DCHECK_EQ(ET_SCROLL_FLING_START, type_);
-    return data_.fling_velocity.y;
+    return data_.fling_start.y;
+  }
+
+  ScrollRailState scroll_rail_state() const {
+    switch(type_) {
+      case ET_GESTURE_SCROLL_UPDATE:
+        return data_.scroll_update.scroll_rail_state;
+      case ET_SCROLL_FLING_START:
+        return data_.fling_start.scroll_rail_state;
+      default:
+        NOTREACHED() << "Can't get scroll rail state for event type " << type_;
+    }
+    return ScrollRailState::Free;
   }
 
   float first_finger_width() const {
@@ -161,6 +179,7 @@ struct EVENTS_BASE_EXPORT GestureEventDetails {
       // Whether any previous scroll update in the current scroll sequence was
       // suppressed because the underlying touch was consumed.
       bool previous_update_in_sequence_prevented;
+      ScrollRailState scroll_rail_state;
     } scroll_update;
 
     float scale;  // PINCH scale.
@@ -168,7 +187,8 @@ struct EVENTS_BASE_EXPORT GestureEventDetails {
     struct {  // FLING velocity.
       float x;
       float y;
-    } fling_velocity;
+      ScrollRailState scroll_rail_state;
+    } fling_start;
 
     // Dimensions of the first finger's enclosing rectangle for
     // TWO_FINGER_TAP.