Add chrome://vr-shell-ui internal page

chrome/common/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/buildflag_header.gni")
 import("//chrome/common/features.gni")
 import("//chrome/version.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//tools/grit/grit_rule.gni")
 
@@ skipping 485 matching lines @@
         "safe_browsing/protobuf_message_read_macros.h",
         "safe_browsing/protobuf_message_size_macros.h",
         "safe_browsing/protobuf_message_write_macros.h",
         "safe_browsing/zip_analyzer.cc",
         "safe_browsing/zip_analyzer.h",
         "safe_browsing/zip_analyzer_results.cc",
         "safe_browsing/zip_analyzer_results.h",
       ]
     }
   }
+
+  if (enable_vr_shell) {
+    defines += [ "ENABLE_VR_SHELL" ]
+  }
 }
 
 process_version("version_header") {
   # TODO(brettw) this should have more reduced visibility, but chrome/browser
   # currently depends on this.
   #visibility = [ ":*" ]
 
   # This one just uses the custom template and no separate sources.
   sources = []
   template_file = "chrome_version.h.in"
@@ skipping 126 matching lines @@
     "resource_usage_reporter.mojom",
     "shell_handler_win.mojom",
   ]
 
   public_deps = [
     "//skia/public/interfaces",
   ]
 
   use_new_wrapper_types = false
 }