fix: clean up implementations of titleBarStyle (#27489)

* Rewrite titleBarStyle impls with WindowButtonsView

* Remove fullscreenWindowTitle option

* Make buttons show correctly under RTL

* Fix docs about traffic lights position

* Fix test on fullscreen resizable

* Fix button states with closabe/minimizable/fullscreenable

* Fix typo

* Deprecate the fullscreenWindowTitle option

shell/browser/ui/cocoa/window_buttons_view.h

@@ -0,0 +1,31 @@
+// Copyright (c) 2021 Microsoft, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#ifndef SHELL_BROWSER_UI_COCOA_WINDOW_BUTTONS_VIEW_H_
+#define SHELL_BROWSER_UI_COCOA_WINDOW_BUTTONS_VIEW_H_
+
+#import <Cocoa/Cocoa.h>
+
+#include "base/mac/scoped_nsobject.h"
+#include "base/optional.h"
+#include "ui/gfx/geometry/point.h"
+
+// Custom Quit, Minimize and Full Screen button container for frameless
+// windows.
+@interface WindowButtonsView : NSView {
+ @private
+  BOOL mouse_inside_;
+  BOOL show_on_hover_;
+  BOOL is_rtl_;
+  gfx::Point margin_;
+  base::scoped_nsobject<NSTrackingArea> tracking_area_;
+}
+
+- (id)initWithMargin:(const base::Optional<gfx::Point>&)margin;
+- (void)setMargin:(const base::Optional<gfx::Point>&)margin;
+- (void)setShowOnHover:(BOOL)yes;
+- (void)setNeedsDisplayForButtons;
+@end
+
+#endif  // SHELL_BROWSER_UI_COCOA_WINDOW_BUTTONS_VIEW_H_