Don't allow font scale to be lower than 1.0

chrome/browser/ui/libgtkui/gtk_ui.cc

 // 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.
 
 #include "chrome/browser/ui/libgtkui/gtk_ui.h"
 
 #include <math.h>
 #include <pango/pango.h>
 #include <X11/Xcursor/Xcursor.h>
 
@@ skipping 346 matching lines @@
   // GTK multiplies the DPI by 1024 before storing it.
   return (gtk_dpi > 0) ? gtk_dpi / 1024.0 : kDefaultDPI;
 }
 
 float GetRawDeviceScaleFactor() {
   if (display::Display::HasForceDeviceScaleFactor())
     return display::Display::GetForcedDeviceScaleFactor();
   return GetDpi() / kDefaultDPI;
 }
 
-// Returns the font size for the *raw* device scale factor in points.
-// The |ui_device_scale_factor| is used to cancel the scale to be applied by UI
-// and to compensate the scale when the device_scale_factor is floored.
-double GetFontSizePixelsInPoint(float ui_device_scale_factor) {
-  // There are 72 points in an inch.
-  double point = GetDpi() / 72.0;
-
-  // Take device_scale_factor into account — if Chrome already scales the
-  // entire UI up by 2x, we should not also scale up.
-  point /= ui_device_scale_factor;
-
-  // Allow the scale lower than 1.0 only for fonts. Don't always use
-  // the raw value however, because the 1.0~1.3 is rounded to 1.0.
-  float raw_scale = GetRawDeviceScaleFactor();
-  if (raw_scale < 1.0f)
-    return point * raw_scale / ui_device_scale_factor;
-  return point;
-}
-
 views::LinuxUI::NonClientMiddleClickAction GetDefaultMiddleClickAction() {
   std::unique_ptr<base::Environment> env(base::Environment::Create());
   switch (base::nix::GetDesktopEnvironment(env.get())) {
     case base::nix::DESKTOP_ENVIRONMENT_KDE4:
     case base::nix::DESKTOP_ENVIRONMENT_KDE5:
       // Starting with KDE 4.4, windows' titlebars can be dragged with the
       // middle mouse button to create tab groups. We don't support that in
       // Chrome, but at least avoid lowering windows in response to middle
       // clicks to avoid surprising users who expect the KDE behavior.
       return views::LinuxUI::MIDDLE_CLICK_ACTION_NONE;
@@ skipping 587 matching lines @@
     // If the size is absolute, it's specified in Pango units. There are
     // PANGO_SCALE Pango units in a device unit (pixel).
     const int size_pixels = pango_font_description_get_size(desc) / PANGO_SCALE;
     default_font_size_pixels_ = size_pixels;
     query.pixel_size = size_pixels;
   } else {
     // Non-absolute sizes are in points (again scaled by PANGO_SIZE).
     // Round the value when converting to pixels to match GTK's logic.
     const double size_points = pango_font_description_get_size(desc) /
                                static_cast<double>(PANGO_SCALE);
-    default_font_size_pixels_ = static_cast<int>(
-        GetFontSizePixelsInPoint(GetDeviceScaleFactor()) * size_points);
+    default_font_size_pixels_ =
+        static_cast<int>(kDefaultDPI / 72.0 * size_points + 0.5);

[oshima, 2017/02/08 21:15:31]

+ 0.5 was a regression in original CL

     query.point_size = static_cast<int>(size_points);
   }
 
   query.style = gfx::Font::NORMAL;
   query.weight =
       static_cast<gfx::Font::Weight>(pango_font_description_get_weight(desc));
   // TODO(davemoore): What about PANGO_STYLE_OBLIQUE?
   if (pango_font_description_get_style(desc) == PANGO_STYLE_ITALIC)
     query.style |= gfx::Font::ITALIC;
 
@@ skipping 38 matching lines @@
 
 float GtkUi::GetDeviceScaleFactor() const {
   return device_scale_factor_;
 }
 
 }  // namespace libgtkui
 
 views::LinuxUI* BuildGtkUi() {
   return new libgtkui::GtkUi;
 }