[Not for review] Demo issue for discussion on https://codereview.chromium.org/2296903002/.

chrome/browser/ui/cocoa/fullscreen_toolbar_controller.h

 // Copyright (c) 2012 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_COCOA_FULLSCREEN_TOOLBAR_CONTROLLER_H_
 #define CHROME_BROWSER_UI_COCOA_FULLSCREEN_TOOLBAR_CONTROLLER_H_
 
 #include <Carbon/Carbon.h>
 #import <Cocoa/Cocoa.h>
 
@@ skipping 12 matching lines @@
                              // shown.
 };
 
 enum HiddenToolbarState {
   TOOLBAR_SHOWN = 0,      // Toolbar fully visible, toolbarFraction is 1.0.
   TOOLBAR_HIDDEN,         // Toolbar fully hidden, toolbarFraction is 0.0.
   TOOLBAR_TRANSITIONING,  // Toolbar in progress of showing/hiding.
                           // toolbarFraction is (0.0, 1.0).
 };
 
+// State of the NSMenuBAr
+enum MenuBarState {
+  MENUBAR_SHOWN = 0,
+  MENUBAR_HIDDEN,
+  MENUBAR_TRANSITIONING
+};
+
 }  // namespace fullscreen_mac
 
 // Provides a controller to fullscreen toolbar for a single browser
 // window.  This class handles running animations, showing and hiding the
 // fullscreen toolbar, and managing the tracking area associated with the
 // toolbar.  This class does not directly manage any views -- the
 // BrowserWindowController is responsible for positioning and z-ordering views.
 //
 
 // TODO (spqchan): Write tests for this class. See crbug.com/640064.
@@ skipping 32 matching lines @@
   // the window is not on the primary screen, this should always be
   // |kFullScreenModeNormal|.  This value can get out of sync with the correct
   // state if we miss a notification (which can happen when a window is closed).
   // Used to track the current state and make sure we properly restore the menu
   // bar when this controller is destroyed.
   base::mac::FullScreenMode systemFullscreenMode_;
 
   // Whether the omnibox is hidden in fullscreen.
   fullscreen_mac::SlidingStyle slidingStyle_;
 
-  // The fraction of the AppKit Menubar that is showing. Ranges from 0 to 1.
-  // Only used in AppKit Fullscreen.
+  // The fraction of the AppKit Menubar that is showing.
   CGFloat menubarFraction_;
 
-  // The state of the toolbar when the sliding style is set to
-  // OMNIBOX_TABS_HIDDEN.
-  fullscreen_mac::HiddenToolbarState hiddenToolbarState_;
+  // The state of the macOS NSMenuBar.
+  MenuBarState menubarState_;
+
+  // Whether the macOS NSMenuBar is animating in or out.
+  bool menubarAnimatingIn_;
 
   // A Carbon event handler that tracks the revealed fraction of the menu bar.
   EventHandlerRef menuBarTrackingHandler_;
 
   // True when the toolbar is dropped to show tabstrip changes.
   BOOL isRevealingToolbarForTabStripChanges_;
 
-  // True when the menubar is disappearing/gone and the toolbar should still be
-  // shown. Set to false after the toolbar hides.
-  BOOL shouldShowToolbarWithoutMenu_;
+  BOOL wasToolbarShowingWhenMenubarStartedAnimatingIn_;
 }
 
 @property(nonatomic, assign) fullscreen_mac::SlidingStyle slidingStyle;
 
 // Designated initializer.
 - (id)initWithBrowserController:(BrowserWindowController*)controller
                           style:(fullscreen_mac::SlidingStyle)style;
 
 // Informs the controller that the browser has entered or exited fullscreen
 // mode. |-setupFullscreenToolbarForContentView:showDropdown:| should be called
@@ skipping 57 matching lines @@
 @interface FullscreenToolbarController (ExposedForTesting)
 // Adjusts the AppKit Fullscreen options of the application.
 - (void)setSystemFullscreenModeTo:(base::mac::FullScreenMode)mode;
 
 // Callback for menu bar animations.
 - (void)setMenuBarRevealProgress:(CGFloat)progress;
 
 @end
 
 #endif  // CHROME_BROWSER_UI_COCOA_FULLSCREEN_TOOLBAR_CONTROLLER_H_