From cabe514431e61bec8a6deb168a3df17fdb0f13f4 Mon Sep 17 00:00:00 2001
From: Samuel Attard <sattard@slack-corp.com>
Date: Fri, 31 Jan 2020 10:27:25 -0800
Subject: [PATCH] chore: add safety checks to RepositionTrafficLights (#21981)

---
 shell/browser/native_window_mac.mm | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/shell/browser/native_window_mac.mm b/shell/browser/native_window_mac.mm
index fea84f1c2614..a02b86139de5 100644
--- a/shell/browser/native_window_mac.mm
+++ b/shell/browser/native_window_mac.mm
@@ -523,6 +523,12 @@ void NativeWindowMac::RepositionTrafficLights() {
   NSButton* miniaturize =
       [window standardWindowButton:NSWindowMiniaturizeButton];
   NSButton* zoom = [window standardWindowButton:NSWindowZoomButton];
+  // Safety check just in case apple changes the view structure in a macOS
+  // update
+  DCHECK(close.superview);
+  DCHECK(close.superview.superview);
+  if (!close.superview || !close.superview.superview)
+    return;
   NSView* titleBarContainerView = close.superview.superview;
 
   // Hide the container when exiting fullscreen, otherwise traffic light buttons