[Mac] Update fullscreen state when window is fullscreened natively.

chrome/browser/ui/cocoa/apps/native_app_window_cocoa.h

Index: chrome/browser/ui/cocoa/apps/native_app_window_cocoa.h
diff --git a/chrome/browser/ui/cocoa/apps/native_app_window_cocoa.h b/chrome/browser/ui/cocoa/apps/native_app_window_cocoa.h
index 716c5739b04d96f97bc517bff0dcbd009915dcd4..7c334ea5a4426c1296033188bd2d1a253e5d09c6 100644
--- a/chrome/browser/ui/cocoa/apps/native_app_window_cocoa.h
+++ b/chrome/browser/ui/cocoa/apps/native_app_window_cocoa.h
@@ -101,6 +101,12 @@ class NativeAppWindowCocoa : public apps::NativeAppWindow,
   // Called when the window is zoomed (maximized or de-maximized).
   void WindowWillZoom();
 
+  // Called when the window enters fullscreen.
+  void WindowDidEnterFullscreen();
+
+  // Called when the window exits fullscreen.
+  void WindowDidExitFullscreen();
+
   // Called to handle a key event.
   bool HandledByExtensionCommand(NSEvent* event);