Create ScreenWin::GetSystemMetricsInDIP and Correctly Deprecate display::win::GetSystemMetricsInDIP

ui/display/win/screen_win.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_DISPLAY_WIN_SCREEN_WIN_H_
 #define UI_DISPLAY_WIN_SCREEN_WIN_H_
 
 #include <windows.h>
 
 #include <memory>
@@ skipping 72 matching lines @@
 
   // Converts a physical size to a DIP size.
   // The DPI scale is performed relative to the display nearest to |hwnd|.
   static gfx::Size ScreenToDIPSize(HWND hwnd, const gfx::Size& size_in_pixels);
 
   // Converts a DIP size to a physical size.
   // The DPI scale is performed relative to the display nearest to |hwnd|.
   static gfx::Size DIPToScreenSize(HWND hwnd, const gfx::Size& dip_size);
 
   // Returns the result of GetSystemMetrics for |metric| scaled to |hwnd|'s DPI.
+  // Use this function if you're already working with screen pixels, as this
+  // helps reduce any cascading rounding errors from DIP to the |hwnd|'s DPI.
   static int GetSystemMetricsForHwnd(HWND hwnd, int metric);
 
+  // Returns the result of GetSystemMetrics for |metric| in DIP.
+  // Use this function if you need to work in DIP and can tolerate cascading
+  // rounding errors towards screen pixels.
+  static int GetSystemMetricsInDIP(int metric);
+
   // Returns |hwnd|'s scale factor.
   static float GetScaleFactorForHWND(HWND hwnd);
 
   // Returns the HWND associated with the NativeView.
   virtual HWND GetHWNDFromNativeView(gfx::NativeView window) const;
 
   // Returns the NativeView associated with the HWND.
   virtual gfx::NativeWindow GetNativeWindowFromHWND(HWND hwnd) const;
 
  protected:
@@ skipping 73 matching lines @@
   // Current list of ScreenWinDisplays.
   std::vector<ScreenWinDisplay> screen_win_displays_;
 
   DISALLOW_COPY_AND_ASSIGN(ScreenWin);
 };
 
 }  // namespace win
 }  // namespace display
 
 #endif  // UI_DISPLAY_WIN_SCREEN_WIN_H_