Implement a Menu Item to Hide the Toolbar in Fullscreen

chrome/browser/ui/exclusive_access/exclusive_access_context.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_EXCLUSIVE_ACCESS_EXCLUSIVE_ACCESS_CONTEXT_H_
 #define CHROME_BROWSER_UI_EXCLUSIVE_ACCESS_EXCLUSIVE_ACCESS_CONTEXT_H_
 
 #include "chrome/browser/ui/exclusive_access/exclusive_access_bubble_type.h"
 
 class GURL;
@@ skipping 18 matching lines @@
   virtual bool IsFullscreen() const = 0;
 
   // Returns true if fullscreen with toolbar is supported.
   virtual bool SupportsFullscreenWithToolbar() const;
 
   // Shows or hides the tab strip, toolbar and bookmark bar with in browser
   // fullscreen.
   // Currently only supported on Mac.
   virtual void UpdateFullscreenWithToolbar(bool with_toolbar);
 
+  // Toggles the toolbar state to be hidden or shown in fullscreen.
+  // Currently only supported on Mac.
+  virtual void ToggleFullscreenToolbar();
+
   // Returns true if the window is fullscreen with additional UI elements. See
   // EnterFullscreen |with_toolbar|.
   virtual bool IsFullscreenWithToolbar() const = 0;
 
   // Enters fullscreen and update exit bubble.
   // On Mac, the tab strip and toolbar will be shown if |with_toolbar| is true,
   // |with_toolbar| is ignored on other platforms.
   virtual void EnterFullscreen(const GURL& url,
                                ExclusiveAccessBubbleType bubble_type,
                                bool with_toolbar) = 0;
@@ skipping 22 matching lines @@
   // hide/unhide its download shelf widget when it is instructed to enter/exit
   // fullscreen mode.
   // Displays the download shelf associated with currently active window.
   virtual void UnhideDownloadShelf();
 
   // Hides download shelf associated with currently active window.
   virtual void HideDownloadShelf();
 };
 
 #endif  // CHROME_BROWSER_UI_EXCLUSIVE_ACCESS_EXCLUSIVE_ACCESS_CONTEXT_H_