Add GN build for Linux sandbox.

ui/gl/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")
 if (is_android) {
   import("//build/config/android/rules.gni")
 }
 
 gl_binding_output_dir = target_gen_dir
@@ skipping 157 matching lines @@
       "$gl_binding_output_dir/gl_bindings_autogen_glx.h",
     ]
 
     configs += [
       "//build/config/linux:x11",
       "//build/config/linux:xcomposite",
       "//build/config/linux:xext",
     ]
 
     deps += [
-      "//ui/gfx/x",
+      "//ui/gfx:gfx_x11",
     ]
   }
   if (is_win) {
     sources += [
       "gl_context_wgl.cc",
       "gl_context_wgl.h",
       "gl_egl_api_implementation.cc",
       "gl_egl_api_implementation.h",
       "gl_surface_wgl.cc",
       "gl_surface_wgl.h",
@@ skipping 114 matching lines @@
 
 if (is_android) {
   generate_jni("gl_jni_headers") {
     sources = [
       "../android/java/src/org/chromium/ui/gl/SurfaceTextureListener.java",
       "../android/java/src/org/chromium/ui/gl/SurfaceTexturePlatformWrapper.java",
     ]
     jni_package = "ui/gl"
   }
 }