Fix font sizes being incorrect when using --force-device-scale-factor.

ui/display/win/screen_win.h

Index: ui/display/win/screen_win.h
diff --git a/ui/display/win/screen_win.h b/ui/display/win/screen_win.h
index 94379e055f3245938004c1689456f803f0aad7c9..5a000d4038521660ae69e53891f2ffc649947812 100644
--- a/ui/display/win/screen_win.h
+++ b/ui/display/win/screen_win.h
@@ -102,6 +102,13 @@ class DISPLAY_EXPORT ScreenWin : public Screen {
   // Returns |hwnd|'s scale factor.
   static float GetScaleFactorForHWND(HWND hwnd);
 
+  // Returns the system's global scale factor, ignoring the value of
+  // --force-device-scale-factor. Only use this if you are working with Windows
+  // metrics global to the system. Otherwise you should call
+  // GetScaleFactorForHWND() to get the correct scale factor for the monitor
+  // you are targeting.
+  static float GetSystemScaleFactor();
+
   // Returns the HWND associated with the NativeView.
   virtual HWND GetHWNDFromNativeView(gfx::NativeView window) const;