Extract the Skia implementation of HarfBuzz font to its own file

ui/gfx/gfx.gyp

 # Copyright (c) 2013 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 164 matching lines @@
         'font_render_params_android.cc',
         'font_render_params_linux.cc',
         'font_render_params_mac.cc',
         'font_render_params_win.cc',
         'frame_time.h',
         'gfx_export.h',
         'gfx_paths.cc',
         'gfx_paths.h',
         'gpu_memory_buffer.cc',
         'gpu_memory_buffer.h',
+        'harfbuzz_font_skia.cc',
+        'harfbuzz_font_skia.h',
         'image/canvas_image_source.cc',
         'image/canvas_image_source.h',
         'image/image.cc',
         'image/image.h',
         'image/image_family.cc',
         'image/image_family.h',
         'image/image_ios.mm',
         'image/image_mac.mm',
         'image/image_png_rep.cc',
         'image/image_png_rep.h',
@@ skipping 287 matching lines @@
          ],
          'variables': {
            'jni_gen_package': 'ui/gfx',
          },
          'includes': [ '../../build/jni_generator.gypi' ],
        },
      ],
     }],
   ],
 }