Move skia related files from content/common/gpu/client to gpu/skia_bindings.

gpu/skia_bindings/skia_bindings.gyp

 # Copyright 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': [
     {
       # GN version: //gpu/skia_bindings
       'target_name': 'gpu_skia_bindings',
       'type': 'static_library',
       'dependencies': [
         '../gpu.gyp:gles2_implementation',
         '../../skia/skia.gyp:skia',
       ],
       'sources': [
         'gl_bindings_skia_cmd_buffer.cc',
         'gl_bindings_skia_cmd_buffer.h',
+        'grcontext_for_gles2_interface.cc',
+        'grcontext_for_gles2_interface.h',
       ],
     }
   ]
 }