Remove unused PlatformFontSkia::typeface() accessor

This accessor is no longer used.

R=asvitkine@chromium.org

Bug: 944227
Change-Id: I60e3ff0ba7790b35afcdb6ecdd5a7faf835d2044
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1719107
Commit-Queue: Etienne Bergeron <etienneb@chromium.org>
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681019}

ui/gfx/platform_font_skia.h

@@ -57,8 +57,6 @@ class GFX_EXPORT PlatformFontSkia : public PlatformFont {
   int GetFontSize() const override;
   const FontRenderParams& GetFontRenderParams() override;
 
-  sk_sp<SkTypeface> typeface() const { return typeface_; }
-
  private:
   // Create a new instance of this object with the specified properties. Called
   // from DeriveFont.