Ensure that trackpad and trackpoint scrolling works on Windows desktop Aura with legacy trackpad dr…

ui/views/win/hwnd_message_handler.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_VIEWS_WIN_HWND_MESSAGE_HANDLER_H_
 #define UI_VIEWS_WIN_HWND_MESSAGE_HANDLER_H_
 
 #include <windows.h>
 #include <atlbase.h>
 #include <atlapp.h>
@@ skipping 306 matching lines @@
     MESSAGE_HANDLER_EX(WM_IME_STARTCOMPOSITION, OnImeMessages)
     MESSAGE_HANDLER_EX(WM_IME_COMPOSITION, OnImeMessages)
     MESSAGE_HANDLER_EX(WM_IME_ENDCOMPOSITION, OnImeMessages)
     MESSAGE_HANDLER_EX(WM_IME_REQUEST, OnImeMessages)
     MESSAGE_HANDLER_EX(WM_IME_NOTIFY, OnImeMessages)
     MESSAGE_HANDLER_EX(WM_CHAR, OnImeMessages)
     MESSAGE_HANDLER_EX(WM_SYSCHAR, OnImeMessages)
     MESSAGE_HANDLER_EX(WM_DEADCHAR, OnImeMessages)
     MESSAGE_HANDLER_EX(WM_SYSDEADCHAR, OnImeMessages)
 
+    // Scroll events
+    MESSAGE_HANDLER_EX(WM_VSCROLL, OnScrollMessage)
+    MESSAGE_HANDLER_EX(WM_HSCROLL, OnScrollMessage)
+
     // Touch Events.
     MESSAGE_HANDLER_EX(WM_TOUCH, OnTouchEvent)
 
     // Uses the general handler macro since the specific handler macro
     // MSG_WM_NCACTIVATE would convert WPARAM type to BOOL type. The high
     // word of WPARAM could be set when the window is minimized or restored.
     MESSAGE_HANDLER_EX(WM_NCACTIVATE, OnNCActivate)
 
     // This list is in _ALPHABETICAL_ order! OR I WILL HURT YOU.
     MSG_WM_ACTIVATEAPP(OnActivateApp)
@@ skipping 66 matching lines @@
   void OnMoving(UINT param, const RECT* new_bounds);
   LRESULT OnNCActivate(UINT message, WPARAM w_param, LPARAM l_param);
   LRESULT OnNCCalcSize(BOOL mode, LPARAM l_param);
   LRESULT OnNCHitTest(const CPoint& point);
   void OnNCPaint(HRGN rgn);
   LRESULT OnNCUAHDrawCaption(UINT message, WPARAM w_param, LPARAM l_param);
   LRESULT OnNCUAHDrawFrame(UINT message, WPARAM w_param, LPARAM l_param);
   LRESULT OnNotify(int w_param, NMHDR* l_param);
   void OnPaint(HDC dc);
   LRESULT OnReflectedMessage(UINT message, WPARAM w_param, LPARAM l_param);
+  LRESULT OnScrollMessage(UINT message, WPARAM w_param, LPARAM l_param);
   LRESULT OnSetCursor(UINT message, WPARAM w_param, LPARAM l_param);
   void OnSetFocus(HWND last_focused_window);
   LRESULT OnSetIcon(UINT size_type, HICON new_icon);
   LRESULT OnSetText(const wchar_t* text);
   void OnSettingChange(UINT flags, const wchar_t* section);
   void OnSize(UINT param, const CSize& size);
   void OnSysCommand(UINT notification_code, const CPoint& point);
   void OnThemeChanged();
   LRESULT OnTouchEvent(UINT message, WPARAM w_param, LPARAM l_param);
   void OnWindowPosChanging(WINDOWPOS* window_pos);
@@ skipping 104 matching lines @@
 
   // If > 0 indicates a menu is running (we're showing a native menu).
   int menu_depth_;
 
   // A factory used to lookup appbar autohide edges.
   base::WeakPtrFactory<HWNDMessageHandler> autohide_factory_;
 
   // Generates touch-ids for touch-events.
   ui::SequentialIDGenerator id_generator_;
 
+  // Indicates if the window has the WS_VSCROLL and WS_HSCROLL styles set.
+  bool scroll_styles_set_;
+
   DISALLOW_COPY_AND_ASSIGN(HWNDMessageHandler);
 };
 
 // This window property if set on the window does not activate the window for a
 // touch based WM_MOUSEACTIVATE message.
 const wchar_t kIgnoreTouchMouseActivateForWindow[] =
     L"Chrome.IgnoreMouseActivate";
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIN_HWND_MESSAGE_HANDLER_H_