Audit and Deprecate DPI Functions in display::win

ui/display/win/dpi.h

 // Copyright 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_DPI_H_
 #define UI_DISPLAY_WIN_DPI_H_
 
 #include "ui/display/display_export.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace display {
 namespace win {
 
+// Deprecated. Use --force-device-scale-factor instead.
+//
 // Sets the device scale factor that will be used unless overridden on the
-// command line by --force-device-scale-factor.  If this is not called, and that
-// flag is not used, the scale factor used by the DIP conversion functions below
-// will be that returned by GetDPIScale().
+// command line by --force-device-scale-factor.
 DISPLAY_EXPORT void SetDefaultDeviceScaleFactor(float scale);
 
-// Gets the scale factor of the display. For example, if the display DPI is
-// 96 then the scale factor is 1.0.
+// Deprecated. Use display::win::ScreenWin::GetScaleFactorForHWND instead.
+//
+// Gets the system's scale factor. For example, if the system DPI is 96 then the
+// scale factor is 1.0. This does not handle per-monitor DPI.
 DISPLAY_EXPORT float GetDPIScale();
 
 // Returns the equivalent DPI for |device_scaling_factor|.
 DISPLAY_EXPORT int GetDPIFromScalingFactor(float device_scaling_factor);
 
 // Returns the equivalent scaling factor for |dpi|.
 DISPLAY_EXPORT float GetScalingFactorFromDPI(int dpi);
 
+// Deprecated. Use display::win::ScreenWin::GetSystemMetricsForHwnd instead.
+//
 // Win32's GetSystemMetrics uses pixel measures. This function calls
-// GetSystemMetrics for the given |metric|, then converts the result to DIP.
+// GetSystemMetrics for the given |metric|, then converts the result using the
+// system's DPI to DIP. This does not handle per-monitor DPI.
 DISPLAY_EXPORT int GetSystemMetricsInDIP(int metric);
 
 }  // namespace win
 }  // namespace display
 
 #endif  // UI_DISPLAY_WIN_DPI_H_