[Mac] Refactor the fullscreen toolbar mouse tracker

chrome/browser/ui/cocoa/fullscreen/fullscreen_toolbar_mouse_tracker.h

+// Copyright 2016 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_FULLSCREEN_TOOLBAR_MOUSE_TRACKER_H_
+#define CHROME_BROWSER_UI_COCOA_FULLSCREEN_FULLSCREEN_TOOLBAR_MOUSE_TRACKER_H_
+
+#import <Cocoa/Cocoa.h>
+
+class FullscreenToolbarAnimationController;
+@class FullscreenToolbarController;
+
+// Class that tracks mouse interactions with the fullscreen toolbar.
+@interface FullscreenToolbarMouseTracker : NSObject
+
+// Designated initializer.
+- (instancetype)
+initWithFullscreenToolbarController:(FullscreenToolbarController*)owner
+                animationController:
+                    (FullscreenToolbarAnimationController*)animationController;
+
+// Updates the tracking area's frame to the given toolbar frame.
+- (void)updateToolbarFrame:(NSRect)frame;
+
+// Updates the tracking area. Remove it if the toolbar isn't fully shown.
+- (void)updateTrackingArea;
+
+// Removes the tracking area.
+- (void)removeTrackingArea;
+
+// Returns YES if the mouse is inside the tracking area.
+- (BOOL)mouseInsideTrackingArea;
+
+@end
+
+#endif  // CHROME_BROWSER_UI_COCOA_FULLSCREEN_FULLSCREEN_TOOLBAR_MOUSE_TRACKER_H_