GN: Fix missing dep (//ui/gl:test_support) in message_center_unittests

ui/message_center/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/features.gni")
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 
 component("message_center") {
   deps = [
@@ skipping 182 matching lines @@
     "//base",
     "//base/allocator",
     "//base/test:test_support",
     "//skia",
     "//testing/gtest",
     "//ui/base",
     "//ui/events",
     "//ui/gfx",
     "//ui/gfx/geometry",
     "//ui/gl",
+    "//ui/gl:test_support",
     "//ui/resources",
     "//ui/resources:ui_test_pak",
     "//url",
   ]
 
   if (enable_notifications && !is_android) {
     sources += [
       "cocoa/notification_controller_unittest.mm",
       "cocoa/popup_collection_unittest.mm",
       "cocoa/popup_controller_unittest.mm",
@@ skipping 22 matching lines @@
       deps += [
         # Compositor is needed by message_center_view_unittest.cc and for the
         # fonts used by bounded_label_unittest.cc.
         "//ui/compositor",
         "//ui/views",
         "//ui/views:test_support",
       ]
     }
   }  # enable_notifications && !is_android
 }