Extract the Skia implementation of HarfBuzz font to its own file

ui/gfx/BUILD.gn

 # 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.
 
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 
 if (is_android) {
   import("//build/config/android/config.gni")
   import("//build/config/android/rules.gni")
@@ skipping 228 matching lines @@
     "//skia",
     "//third_party/icu",
   ]
 
   # Text rendering conditions (complicated so separated out).
   if (is_android || is_ios) {
     # We don't support RenderText on these platforms.
   } else {
     # Mac doesn't use RenderTextHarfBuzz by default yet.
     sources += [
+      "harfbuzz_font_skia.cc",
+      "harfbuzz_font_skia.h",
       "render_text.cc",
       "render_text.h",
       "render_text_harfbuzz.cc",
       "render_text_harfbuzz.h",
       "render_text_mac.cc",
       "render_text_mac.h",
       "text_utils_skia.cc",
     ]
   }
 
@@ skipping 288 matching lines @@
 if (is_android) {
   generate_jni("gfx_jni_headers") {
     sources = [
       "../android/java/src/org/chromium/ui/gfx/BitmapHelper.java",
       "../android/java/src/org/chromium/ui/gfx/DeviceDisplayInfo.java",
       "../android/java/src/org/chromium/ui/gfx/ViewConfigurationHelper.java",
     ]
     jni_package = "gfx"
   }
 }