Mac: Implement GetFallbackFontFamilies for Harfbuzz

ui/gfx/font_fallback_mac.cc

Index: ui/gfx/font_fallback_mac.cc
diff --git a/ui/gfx/font_fallback_mac.cc b/ui/gfx/font_fallback_mac.cc
deleted file mode 100644
index 3d96d1173c55c8ce92df9a2033cb2777e1e55353..0000000000000000000000000000000000000000
--- a/ui/gfx/font_fallback_mac.cc
+++ /dev/null
@@ -1,20 +0,0 @@
-// Copyright 2014 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/gfx/font_fallback.h"
-
-#include <string>
-#include <vector>
-
-#include "base/logging.h"
-
-namespace gfx {
-
-std::vector<std::string> GetFallbackFontFamilies(
-    const std::string& font_family) {
-  // TODO(jiangj): Not implemented, see crbug.com/439039.
-  return std::vector<std::string>(1, font_family);
-}
-
-}  // namespace gfx