Introduce WM_POINTER to Handle pointer events with pen type

ui/base/win/window_event_target.h

 // Copyright (c) 2014 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_WIN_WINDOW_EVENT_TARGET_H_
 #define UI_BASE_WIN_WINDOW_EVENT_TARGET_H_
 
 #include <windows.h>
 
 #include "ui/base/ui_base_export.h"
@@ skipping 12 matching lines @@
   // The |w_param| and |l_param| values are dependent on the type of the
   // message.
   // The |handled| parameter is an output parameter which when set to false
   // indicates that the message should be DefProc'ed.
   // Returns the result of processing the message.
   virtual LRESULT HandleMouseMessage(unsigned int message,
                                      WPARAM w_param,
                                      LPARAM l_param,
                                      bool* handled) = 0;
 
+  // Handles pointer events like WM_POINTERUP, WM_POINTERDOWN, WM_POINTERUPDATE
+  // events.
+  // The |message| parameter identifies the message.
+  // The |w_param| and |l_param| values are as per MSDN docs.
+  // The |handled| parameter is an output parameter which when set to false
+  // indicates that the message should be DefProc'ed.
+  // Returns the result of processing the message.
+  virtual LRESULT HandlePointerMessage(unsigned int message,
+                                       WPARAM w_param,
+                                       LPARAM l_param,
+                                       bool* handled) = 0;
+
   // Handles keyboard events like WM_KEYDOWN/WM_KEYUP, etc.
   // The |message| parameter identifies the message.
   // The |w_param| and |l_param| values are dependent on the type of the
   // message.
   // The |handled| parameter is an output parameter which when set to false
   // indicates that the message should be DefProc'ed.
   // Returns the result of processing the message.
   virtual LRESULT HandleKeyboardMessage(unsigned int message,
                                         WPARAM w_param,
                                         LPARAM l_param,
@@ skipping 37 matching lines @@
  protected:
   WindowEventTarget();
   virtual ~WindowEventTarget();
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_WIN_WINDOW_EVENT_TARGET_H_