Remove enable_webvr from build/config, and move it to the buildflag_header system.

chrome/browser/ui/webui/chrome_web_ui_controller_factory.cc

Index: chrome/browser/ui/webui/chrome_web_ui_controller_factory.cc
diff --git a/chrome/browser/ui/webui/chrome_web_ui_controller_factory.cc b/chrome/browser/ui/webui/chrome_web_ui_controller_factory.cc
index df5e8b387a6eb692b867c961469779ac4a791277..5be5b1ff8e98754315b7ea9c5559b7d09498c206 100644
--- a/chrome/browser/ui/webui/chrome_web_ui_controller_factory.cc
+++ b/chrome/browser/ui/webui/chrome_web_ui_controller_factory.cc
@@ -81,6 +81,7 @@
 #include "content/public/browser/web_ui.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/url_utils.h"
+#include "device/vr/features.h"
 #include "extensions/features/features.h"
 #include "media/media_features.h"
 #include "ppapi/features/features.h"
@@ -116,7 +117,7 @@
 #include "chrome/browser/ui/webui/popular_sites_internals_ui.h"
 #include "chrome/browser/ui/webui/snippets_internals_ui.h"
 #include "chrome/browser/ui/webui/webapks_ui.h"
-#if defined(ENABLE_WEBVR)
+#if BUILDFLAG(ENABLE_WEBVR)
 #include "chrome/browser/ui/webui/vr_shell/vr_shell_ui_ui.h"
 #endif
 #else
@@ -522,7 +523,7 @@ WebUIFactoryFunction GetWebUIFactoryFunction(WebUI* web_ui,
     return &NewWebUI<SnippetsInternalsUI>;
   if (url.host_piece() == chrome::kChromeUIWebApksHost)
     return &NewWebUI<WebApksUI>;
-#if defined(ENABLE_WEBVR)
+#if BUILDFLAG(ENABLE_WEBVR)
   if (url.host_piece() == chrome::kChromeUIVrShellUIHost)
     return &NewWebUI<VrShellUIUI>;
 #endif