touchui: support XInput2 MT

views/touchui/touch_factory.h

Index: views/touchui/touch_factory.h
diff --git a/views/touchui/touch_factory.h b/views/touchui/touch_factory.h
index b18d8c38edede77969c88d8c703ddddf2381e6dd..f6ccadfe03ca6c866607f11826d981efa48b12b1 100644
--- a/views/touchui/touch_factory.h
+++ b/views/touchui/touch_factory.h
@@ -29,24 +29,10 @@ class VIEWS_EXPORT TouchFactory {
     TP_TOUCH_MINOR,       // Width of the touch area.
     TP_ORIENTATION,       // Angle between the X-axis and the major axis of the
                           // touch area.
+    TP_POSITION_X,        // Position X
+    TP_POSITION_Y,        // Position Y
+    TP_TRACKING_ID,       // Tracking ID
     TP_PRESSURE,          // Pressure of the touch contact.
-
-    // NOTE: A touch event can have multiple touch points. So when we receive a
-    // touch event, we need to determine which point triggered the event.
-    // A touch point can have both a 'Slot ID' and a 'Tracking ID', and they can
-    // be (in fact, usually are) different. The 'Slot ID' ranges between 0 and
-    // (X - 1), where X is the maximum touch points supported by the device. The
-    // 'Tracking ID' can be any 16-bit value. With XInput 2.0, an XI_Motion
-    // event that comes from a currently-unused 'Slot ID' indicates the creation
-    // of a new touch point, and any event that comes with a 0 value for
-    // 'Tracking ID' marks the removal of a touch point. During the lifetime of
-    // a touchpoint, we use the 'Slot ID' as its identifier. The XI_ButtonPress
-    // and XI_ButtonRelease events are ignored.
-    TP_SLOT_ID,           // ID of the finger that triggered a touch event
-                          // (useful when tracking multiple simultaneous
-                          // touches)
-    TP_TRACKING_ID,       // ID of the touch point.
-
     TP_LAST_ENTRY
   };
 
@@ -71,12 +57,6 @@ class VIEWS_EXPORT TouchFactory {
   // Is the device a touch-device?
   bool IsTouchDevice(unsigned int deviceid) const;
 
-  // Is the slot ID currently used?
-  bool IsSlotUsed(int slot) const;
-
-  // Marks a slot as being used/unused.
-  void SetSlotUsed(int slot, bool used);
-
   // Grabs the touch devices for the specified window on the specified display.
   // Returns if grab was successful for all touch devices.
   bool GrabTouchDevices(Display* display, ::Window window);
@@ -185,9 +165,6 @@ class VIEWS_EXPORT TouchFactory {
   // Maximum simultaneous touch points.
   static const int kMaxTouchPoints = 32;
 
-  // A lookup table for slots in use for a touch event.
-  std::bitset<kMaxTouchPoints> slots_used_;
-
   DISALLOW_COPY_AND_ASSIGN(TouchFactory);
 };