Add VrShell feature flag and wire it up to VrShell delegate.

content/public/common/content_features.cc

 // Copyright 2015 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.
 
 #include "build/build_config.h"
 #include "content/public/common/content_features.h"
 
 namespace features {
 
 // All features in alphabetical order.
@@ skipping 171 matching lines @@
 
 // Enables token binding
 // (https://www.ietf.org/id/draft-ietf-tokbind-protocol-04.txt).
 const base::Feature kTokenBinding{"token-binding",
                                   base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Enables touchpad and wheel scroll latching.
 const base::Feature kTouchpadAndWheelScrollLatching{
     "TouchpadAndWheelScrollLatching", base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Enables VR UI.
+const base::Feature kVrShell{"VrShell", base::FEATURE_DISABLED_BY_DEFAULT};
+
 // Enable WebAssembly.
 // http://webassembly.org/
 const base::Feature kWebAssembly{"WebAssembly",
                                  base::FEATURE_DISABLED_BY_DEFAULT};
 
 // If WebGL Image Chromium is allowed, this feature controls whether it is
 // enabled.
 const base::Feature kWebGLImageChromium{"WebGLImageChromium",
                                         base::FEATURE_ENABLED_BY_DEFAULT};
 
@@ skipping 37 matching lines @@
 #endif
 
 #if defined(OS_WIN)
 // Emergency "off switch" for new Windows sandbox security mitigation,
 // sandbox::MITIGATION_EXTENSION_POINT_DISABLE.
 const base::Feature kWinSboxDisableExtensionPoints{
     "WinSboxDisableExtensionPoint", base::FEATURE_ENABLED_BY_DEFAULT};
 #endif
 
 }  // namespace features