Updates subpixel positioning and hinting when DSF is changed

ui/gfx/platform_font_pango.h

Index: ui/gfx/platform_font_pango.h
diff --git a/ui/gfx/platform_font_pango.h b/ui/gfx/platform_font_pango.h
index e70dd6adbac12a80824094ac1563f3653757144f..1393063651575c334a75a1b110a5b049a29e6520 100644
--- a/ui/gfx/platform_font_pango.h
+++ b/ui/gfx/platform_font_pango.h
@@ -94,9 +94,14 @@ class GFX_EXPORT PlatformFontPango : public PlatformFont {
   std::string font_family_;
   int font_size_pixels_;
   int style_;
+#if defined(OS_CHROMEOS)
+  // mutable to be updated in GetFontRenderParams().
+  mutable float device_scale_factor_;

[Daniel Erat, 2014/12/12 15:54:58]

instead of making these mutable, would you mind just making
GetFontRenderParams() be non-const?

[Jun Mukai, 2014/12/12 19:40:12]

Done.

+#endif
 
-  // Information describing how the font should be rendered.
-  FontRenderParams font_render_params_;
+  // Information describing how the font should be rendered. This parameter is
+  // mutable to update in GetFontRenderParams().
+  mutable FontRenderParams font_render_params_;
 
   // Cached metrics, generated at construction.
   int ascent_pixels_;