Support multi touch on Windows 8 AURA and ASH.

ui/views/win/hwnd_message_handler.cc

Index: ui/views/win/hwnd_message_handler.cc
===================================================================
--- ui/views/win/hwnd_message_handler.cc	(revision 190807)
+++ ui/views/win/hwnd_message_handler.cc	(working copy)
@@ -12,6 +12,7 @@
 #include "base/win/windows_version.h"
 #include "ui/base/events/event.h"
 #include "ui/base/events/event_utils.h"
+#include "ui/base/gestures/gesture_sequence.h"
 #include "ui/base/keycodes/keyboard_code_conversion_win.h"
 #include "ui/base/win/hwnd_util.h"
 #include "ui/base/win/mouse_wheel_util.h"
@@ -292,10 +293,6 @@
 // The thickness of an auto-hide taskbar in pixels.
 const int kAutoHideTaskbarThicknessPx = 2;
 
-// The touch id to be used for touch events coming in from Windows Aura
-// Desktop.
-const int kDesktopChromeAuraTouchId = 9;
-
 // For windows with the standard frame removed, the client area needs to be
 // different from the window area to avoid a "feature" in Windows's handling of
 // WM_NCCALCSIZE data. See the comment near the bottom of GetClientAreaInsets
@@ -2003,7 +2000,7 @@
         ui::TouchEvent event(
             touch_event_type,
             gfx::Point(point.x, point.y),
-            kDesktopChromeAuraTouchId,
+            input[i].dwID % ui::GestureSequence::kMaxGesturePoints,
             base::TimeDelta::FromMilliseconds(input[i].dwTime));
         delegate_->HandleTouchEvent(event);
       }