Call EnableNonClientDpiScaling

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 <stddef.h>
@@ skipping 393 matching lines @@
     CR_MSG_WM_ENTERSIZEMOVE(OnEnterSizeMove)
     CR_MSG_WM_ERASEBKGND(OnEraseBkgnd)
     CR_MSG_WM_EXITSIZEMOVE(OnExitSizeMove)
     CR_MSG_WM_GETMINMAXINFO(OnGetMinMaxInfo)
     CR_MSG_WM_INITMENU(OnInitMenu)
     CR_MSG_WM_INPUTLANGCHANGE(OnInputLangChange)
     CR_MSG_WM_KILLFOCUS(OnKillFocus)
     CR_MSG_WM_MOVE(OnMove)
     CR_MSG_WM_MOVING(OnMoving)
     CR_MSG_WM_NCCALCSIZE(OnNCCalcSize)
+    CR_MSG_WM_NCCREATE(OnNCCreate)
     CR_MSG_WM_NCHITTEST(OnNCHitTest)
     CR_MSG_WM_NCPAINT(OnNCPaint)
     CR_MSG_WM_NOTIFY(OnNotify)
     CR_MSG_WM_PAINT(OnPaint)
     CR_MSG_WM_SETFOCUS(OnSetFocus)
     CR_MSG_WM_SETICON(OnSetIcon)
     CR_MSG_WM_SETTEXT(OnSetText)
     CR_MSG_WM_SETTINGCHANGE(OnSettingChange)
     CR_MSG_WM_SIZE(OnSize)
     CR_MSG_WM_SYSCOMMAND(OnSysCommand)
@@ skipping 31 matching lines @@
   void OnInputLangChange(DWORD character_set, HKL input_language_id);
   LRESULT OnKeyEvent(UINT message, WPARAM w_param, LPARAM l_param);
   void OnKillFocus(HWND focused_window);
   LRESULT OnMouseActivate(UINT message, WPARAM w_param, LPARAM l_param);
   LRESULT OnMouseRange(UINT message, WPARAM w_param, LPARAM l_param);
   LRESULT OnPointerActivate(UINT message, WPARAM w_param, LPARAM l_param);
   void OnMove(const gfx::Point& point);
   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 OnNCCreate(LPCREATESTRUCT lpCreateStruct);
   LRESULT OnNCHitTest(const gfx::Point& 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);
@@ skipping 95 matching lines @@
 
   // The icon created from the bitmap image of the window icon.
   base::win::ScopedHICON window_icon_;
 
   // The icon created from the bitmap image of the app icon.
   base::win::ScopedHICON app_icon_;
 
   // The current DPI.
   int dpi_;
 
+  // Whether EnableNonClientDpiScaling was called successfully with this window.

[sky, 2016/12/14 02:42:41]

Can you describe what that means (folks looking at this class won't necessarily
know what this means).

[robliao, 2016/12/14 18:50:19]

Done.

  // Whether EnableNonClientDpiScaling was called successfully with this window.
  // This flag exists because EnableNonClientDpiScaling must be called during
  // WM_NCCREATE and EnableChildWindowDpiMessage is called after window
  // creation. We don't want to call both, so this helps us determine if a call
  // to EnableChildWindowDpiMessage is necessary.

[sky, 2016/12/14 18:54:24]

Excellent! But I was hoping you would describe what EnableNonClientDpiScaling()
does. But I'm ok with the improved description here.

[robliao, 2016/12/14 19:03:18]

EnableNonClientDpiScaling is a public Windows function; I defer to MSDN for that
(https://msdn.microsoft.com/en-us/library/windows/desktop/mt748621(v=vs.85).aspx)

+  bool called_enable_non_client_dpi_scaling_;
+
   // Event handling ------------------------------------------------------------
 
   // The flags currently being used with TrackMouseEvent to track mouse
   // messages. 0 if there is no active tracking. The value of this member is
   // used when tracking is canceled.
   DWORD active_mouse_tracking_flags_;
 
   // Set to true when the user presses the right mouse button on the caption
   // area. We need this so we can correctly show the context menu on mouse-up.
   bool is_right_mouse_pressed_on_caption_;
@@ skipping 110 matching lines @@
 
   // The factory used with BEGIN_SAFE_MSG_MAP_EX.
   base::WeakPtrFactory<HWNDMessageHandler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(HWNDMessageHandler);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIN_HWND_MESSAGE_HANDLER_H_