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..272d74736a82f61a53f11bc1bc3c4416769ba48b 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 on.

[robliao, 2017/02/15 22:59:41]

Nit: correct scale factor for the target monitor.
Ending sentences with a preposition :-D.

[Bret, 2017/02/15 23:13:46]

Okay, Bishop Lowth. I edited it anyway since target is more generic than what
monitor you're drawing to.

+  static float GetSystemScaleFactor();
+
   // Returns the HWND associated with the NativeView.
   virtual HWND GetHWNDFromNativeView(gfx::NativeView window) const;