RenderTextHarfBuzz: Implement font fallback for Win and Linux

ui/gfx/font_fallback_mac.cc

+// 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"
+
+namespace gfx {
+
+std::vector<std::string> GetFallbackFontFamilies(std::string font_family) {

[msw, 2014/06/30 17:35:54]

Do we need a stubbed impl for iOS, Android, etc.?

[ckocagil, 2014/07/04 15:30:15]

I'll add stubs as we get compile failures in CQ or tree.

+  NOTIMPLEMENTED();
+  return std::vector<std::string>(1, font_family);
+}
+
+}  // namespace gfx