Remove ENABLE_VR_SHELL compile-time 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 3466 matching lines @@
     ]
   }
 
   if (!is_chrome_branded) {
     sources += [
       "search/local_files_ntp_source.cc",
       "search/local_files_ntp_source.h",
     ]
   }
 
-  if (enable_vr_shell || enable_webvr) {
-    if (enable_vr_shell) {
-      defines += [ "ENABLE_VR_SHELL" ]
-    }
-
+  if (enable_webvr) {
     deps += [ "android/vr_shell:vr_common" ]
     configs += [ "//third_party/gvr-android-sdk:libgvr_config" ]
   }
 
   if (is_mac) {
     deps += [
       "//chrome/app_shim",
       "//chrome/browser/apps/app_shim",
       "//chrome/browser/ui/cocoa/notifications:common",
       "//third_party/crashpad/crashpad/client:client",
@@ skipping 1024 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"
 }