Add OzoneGLImpl interface.

ui/gl/init/BUILD.gn

 # Copyright 2016 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")
 
 component("init") {
   output_name = "gl_init"
 
   public = [
@@ skipping 40 matching lines @@
     sources += [
       "gl_factory_x11.cc",
       "gl_initializer_x11.cc",
     ]
 
     deps += [ "//ui/gfx/x" ]
   } else if (use_ozone) {
     sources += [
       "gl_factory_ozone.cc",
       "gl_initializer_ozone.cc",
+      "ozone_util.h",
     ]
 
     deps += [ "//ui/ozone" ]
   }
 }