Remove ui_compositor_image_transport, it has no effect.

chrome/browser/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/chrome_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/split_static_library.gni")
 import("//chrome/common/features.gni")
@@ skipping 2299 matching lines @@
     deps += [
       "//content/public/common",
       "//services/ui/public/cpp",
       "//services/ui/public/cpp/input_devices",
       "//ui/aura",
       "//ui/compositor",
       "//ui/snapshot",
       "//ui/views/mus",
     ]
   }
-  if (ui_compositor_image_transport) {
-    deps += [ "//ui/gl" ]
-  }
 
   if (use_ash) {
     # Cross-platform Ash sources.
     sources += [
       "media/webrtc/desktop_media_list_ash.cc",
       "media/webrtc/desktop_media_list_ash.h",
       "renderer_context_menu/open_with_menu_factory_ash.cc",
       "renderer_context_menu/open_with_menu_factory_ash.h",
       "signin/signin_error_notifier_ash.cc",
       "signin/signin_error_notifier_ash.h",
@@ skipping 2221 matching lines @@
       "media/pepper_cdm_test_constants.cc",
       "media/pepper_cdm_test_constants.h",
     ]
   }
 }
 
 service_manifest("preferences_manifest") {
   name = "preferences"
   source = "prefs/preferences_manifest.json"
 }