Add support for maintaining ordinal values through GestureRecognizer

ui/base/gestures/gesture_types.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_BASE_GESTURES_GESTURE_TYPES_H_
 #define UI_BASE_GESTURES_GESTURE_TYPES_H_
 
 #include "base/logging.h"
 #include "ui/base/events/event_constants.h"
 #include "ui/gfx/rect.h"
 
 namespace ui {
 
 class GestureEvent;
 class TouchEvent;
 
 struct UI_EXPORT GestureEventDetails {
  public:
   GestureEventDetails(EventType type, float delta_x, float delta_y);
+  GestureEventDetails(EventType type,
+                      float delta_x, float delta_y,
+                      float delta_x_ordinal, float delta_y_ordinal);
 
   EventType type() const { return type_; }
 
   int touch_points() const { return touch_points_; }
   void set_touch_points(int touch_points) { touch_points_ = touch_points; }
 
   const gfx::Rect& bounding_box() const { return bounding_box_; }
   void set_bounding_box(const gfx::Rect& box) { bounding_box_ = box; }
 
-  void SetScrollVelocity(float velocity_x, float velocity_y);
+  void SetScrollVelocity(float velocity_x, float velocity_y,
+                         float velocity_x_ordinal, float velocity_y_ordinal);
 
   float scroll_x() const {
     CHECK_EQ(ui::ET_GESTURE_SCROLL_UPDATE, type_);
     return data.scroll_update.x;
   }
 
   float scroll_y() const {
     CHECK_EQ(ui::ET_GESTURE_SCROLL_UPDATE, type_);
     return data.scroll_update.y;
   }
 
   float velocity_x() const {
     CHECK(type_ == ui::ET_GESTURE_SCROLL_UPDATE ||
           type_ == ui::ET_SCROLL_FLING_START);
     return type_ == ui::ET_SCROLL_FLING_START ? data.fling_velocity.x :
                                                 data.scroll_update.velocity_x;
   }
 
   float velocity_y() const {
     CHECK(type_ == ui::ET_GESTURE_SCROLL_UPDATE ||
           type_ == ui::ET_SCROLL_FLING_START);
     return type_ == ui::ET_SCROLL_FLING_START ? data.fling_velocity.y :
                                                 data.scroll_update.velocity_y;
   }
 
+  // *_ordinal values are unmodified by rail based clamping.
+  float scroll_x_ordinal() const {
+    CHECK_EQ(ui::ET_GESTURE_SCROLL_UPDATE, type_);
+    return data.scroll_update.x_ordinal;
+  }
+
+  float scroll_y_ordinal() const {
+    CHECK_EQ(ui::ET_GESTURE_SCROLL_UPDATE, type_);
+    return data.scroll_update.y_ordinal;
+  }
+
+  float velocity_x_ordinal() const {
+    CHECK(type_ == ui::ET_GESTURE_SCROLL_UPDATE ||
+          type_ == ui::ET_SCROLL_FLING_START);
+    return type_ == ui::ET_SCROLL_FLING_START ?
+        data.fling_velocity.x_ordinal :
+        data.scroll_update.velocity_x_ordinal;
+  }
+
+  float velocity_y_ordinal() const {
+    CHECK(type_ == ui::ET_GESTURE_SCROLL_UPDATE ||
+          type_ == ui::ET_SCROLL_FLING_START);
+    return type_ == ui::ET_SCROLL_FLING_START ?
+        data.fling_velocity.y_ordinal :
+        data.scroll_update.velocity_y_ordinal;
+  }
+
   int touch_id() const {
     CHECK_EQ(ui::ET_GESTURE_LONG_PRESS, type_);
     return data.touch_id;
   }
 
   float first_finger_width() const {
     CHECK_EQ(ui::ET_GESTURE_TWO_FINGER_TAP, type_);
     return data.first_finger_enclosing_rectangle.width;
   }
 
@@ skipping 33 matching lines @@
   }
 
  private:
   ui::EventType type_;
   union {
     struct {  // SCROLL delta.
       float x;
       float y;
       float velocity_x;
       float velocity_y;
+      float x_ordinal;
+      float y_ordinal;
+      float velocity_x_ordinal;
+      float velocity_y_ordinal;
     } scroll_update;
 
     float scale;  // PINCH scale.
 
     struct {  // FLING velocity.
       float x;
       float y;
+      float x_ordinal;
+      float y_ordinal;
     } fling_velocity;
 
     int touch_id;  // LONG_PRESS touch-id.
 
     // Dimensions of the first finger's enclosing rectangle for TWO_FINGER_TAP.
     struct {
       float width;
       float height;
     } first_finger_enclosing_rectangle;
 
@@ skipping 43 matching lines @@
   virtual ~GestureEventHelper() {
   }
 
   virtual bool DispatchLongPressGestureEvent(GestureEvent* event) = 0;
   virtual bool DispatchCancelTouchEvent(TouchEvent* event) = 0;
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_GESTURES_GESTURE_TYPES_H_