Implement a Menu Item to Hide the Toolbar in Fullscreen

chrome/browser/ui/exclusive_access/exclusive_access_context.cc

 // Copyright (c) 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 "chrome/browser/ui/exclusive_access/exclusive_access_context.h"
 
 #include "base/logging.h"
 
 bool ExclusiveAccessContext::SupportsFullscreenWithToolbar() const {
   return false;
 }
 
 void ExclusiveAccessContext::UpdateFullscreenWithToolbar(bool with_toolbar) {
   NOTIMPLEMENTED();
 }
 
+void ExclusiveAccessContext::ToggleFullscreenToolbar() {
+  NOTIMPLEMENTED();
+}
+
 #if defined(OS_WIN)
 void ExclusiveAccessContext::SetMetroSnapMode(bool enable) {
   NOTIMPLEMENTED();
 }
 
 bool ExclusiveAccessContext::IsInMetroSnapMode() const {
   return false;
 }
 #endif  // defined(OS_WIN)
 
 void ExclusiveAccessContext::UnhideDownloadShelf() {
   // NOOP implementation.
 }
 
 void ExclusiveAccessContext::HideDownloadShelf() {
   // NOOP implementation.
 }