Use float literals to decide when to blacklist low scaling factors

chrome/browser/ui/libgtk2ui/gtk2_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/libgtk2ui/gtk2_ui.h"
 
 #include <math.h>
 #include <pango/pango.h>
 #include <set>
 #include <utility>
@@ skipping 1334 matching lines @@
 void Gtk2UI::UpdateDeviceScaleFactor(float device_scale_factor) {
   device_scale_factor_ = device_scale_factor;
   UpdateDefaultFont();
 }
 
 float Gtk2UI::GetDeviceScaleFactor() const {
   if (gfx::Display::HasForceDeviceScaleFactor())
     return gfx::Display::GetForcedDeviceScaleFactor();
   const int kCSSDefaultDPI = 96;
   const float scale = GetDPI() / kCSSDefaultDPI;
-  // Round to 1 decimal, e.g. to 1.4.
-  const float rounded = roundf(scale * 10) / 10;
-  // See crbug.com/484400
-  return rounded < 1.3 ? 1.0 : rounded;
+
+  // Blacklist scaling factors <130% (crbug.com/484400) and round
+  // to 1 decimal to prevent rendering problems (crbug.com/485183).
+  return scale < 1.3f ? 1.0f : roundf(scale * 10) / 10;
 }
 
 }  // namespace libgtk2ui
 
 views::LinuxUI* BuildGtk2UI() {
   return new libgtk2ui::Gtk2UI;
 }