The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5856fd65869e3da2ba7a6c5e7eaacc6681959595

commit 5856fd65869e3da2ba7a6c5e7eaacc6681959595
Author: spqchan <spqchan@chromium.org>
Date: Mon May 07 21:33:54 2018

[Mac] Remove Mac OSX 10.9 code in BrowserWindowController

Bug:  840453 
Change-Id: I76e819cd53b3f834eb6252808e1323080aa69525
Reviewed-on: https://chromium-review.googlesource.com/1048122
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Sarah Chan <spqchan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#556576}
[modify] https://crrev.com/5856fd65869e3da2ba7a6c5e7eaacc6681959595/chrome/browser/ui/cocoa/browser_window_controller_private.h
[modify] https://crrev.com/5856fd65869e3da2ba7a6c5e7eaacc6681959595/chrome/browser/ui/cocoa/browser_window_controller_private.mm