Remove MOJO_SHELL_CLIENT define.

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 602 matching lines @@
       "ui/views/frame/browser_non_client_frame_view_mus.h",
     ]
     deps += [
       "//content/public/common",
       "//services/ui/public/cpp",
       "//services/ui/public/cpp/input_devices",
       "//ui/aura",
       "//ui/compositor",
       "//ui/views/mus",
     ]
-    defines += [ "MOJO_SHELL_CLIENT" ]
   }
   if (ui_compositor_image_transport) {
     deps += [ "//ui/gl" ]
   }
 
   if (use_ash) {
     sources +=
         rebase_path(gypi_values.chrome_browser_ash_sources, ".", "//chrome")
     deps += [ "//ash" ]
   }
@@ skipping 734 matching lines @@
   # linking all of the test support.
   static_library("pepper_cdm_test_constants") {
     testonly = true
     visibility = [ "//chrome/*" ]
     sources = [
       "media/pepper_cdm_test_constants.cc",
       "media/pepper_cdm_test_constants.h",
     ]
   }
 }