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

ui/base/l10n/l10n_util_win.cc

 // Copyright (c) 2011 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.
 
 #include "ui/base/l10n/l10n_util_win.h"
 
 #include <windowsx.h>
 #include <algorithm>
 #include <iterator>
 
@@ skipping 137 matching lines @@
       ui_font_family.empty())
     return false;
   if (override_font_family && font_size_scaler) {
     override_font_family->swap(ui_font_family);
     *font_size_scaler = scaler100 / 100.0;
   }
   return true;
 }
 
 void AdjustUIFont(LOGFONT* logfont) {
-  float dpi_scale = display::win::GetDPIScale();
-  if (display::Display::HasForceDeviceScaleFactor()) {
-    // If the scale is forced, we don't need to adjust it here.
-    dpi_scale = 1.0f;
-  }
-  AdjustUIFontForDIP(dpi_scale, logfont);
+  // Use the unforced scale so the font will be normalized to the correct DIP
+  // value. That way it'll appear the right size when the forced scale is
+  // applied later (when coverting to pixels).
+  AdjustUIFontForDIP(display::win::GetUnforcedDeviceScaleFactor(), logfont);

[robliao, 2017/02/13 17:57:33]

Just to make sure I understand this correctly, the issue here is that the font
system completely works in pixels and we perform a conversion to make things DIP
in views, correct?

If that's the case, then I don't see an alternative other than to provide the
actual DPI to the font system. See comment on display.

[Bret, 2017/02/14 20:29:20]

Our font system works in DIPs, as expected. This value is coming from Windows,
so it's in pixels.

I'm not sure what comment you're referring to.

[robliao, 2017/02/14 20:43:09]

That's fun. I think what I meant to say is let's pipe this through display. 

display::Display already provides the forced DPI, it stands to reason that it
should also provide the unforced one if someone really needs it.

 }
 
 void AdjustUIFontForDIP(float dpi_scale, LOGFONT* logfont) {
   base::string16 ui_font_family = L"default";
   double ui_font_size_scaler = 1;
   if (NeedOverrideDefaultUIFont(&ui_font_family, &ui_font_size_scaler) ||
       dpi_scale != 1) {
     AdjustLogFont(ui_font_family, ui_font_size_scaler, dpi_scale, logfont);
   }
 }
@@ skipping 24 matching lines @@
   } else {
     NOTREACHED() << "Failed to determine the UI language for locale override.";
   }
 }
 
 const std::vector<std::string>& GetLocaleOverrides() {
   return override_locale_holder.Get().value();
 }
 
 }  // namespace l10n_util