From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Charles Kerr <charles@charleskerr.com>
Date: Thu, 20 Sep 2018 17:50:17 -0700
Subject: allow_nested_error_trackers.patch

Only one X11ErrorTracker should exist at a time, but upstream has a bug
where two can exist if running in headless mode --
  ui::(anonymous namespace)::SupportsEWMH() [inner tracker is created]
  ui::WmSupportsHint()
  ui::IsX11WindowFullScreen()
  ui::ScreensaverWindowFinder::IsScreensaverWindow()
  ui::ScreensaverWindowFinder::ShouldStopIterating()
  ui::EnumerateTopLevelWindows()
  ui::ScreensaverWindowFinder::ScreensaverWindowExists() [outer tracker created]
  ui::CheckIdleStateIsLocked()
  ui::CalculateIdleState()
Removal of either tracker could have side-effects in some code paths,
so this is probably better handled upstream. This patch tries to do the
least harm in the interim by removing the check that prevents more than
one tracker from existing at a time.

diff --git a/ui/gfx/x/x11_error_tracker.cc b/ui/gfx/x/x11_error_tracker.cc
index 6592ae0483884815697358040123eed5ee657816..d6862673c0b5a61db550c084291787ad1549db69 100644
--- a/ui/gfx/x/x11_error_tracker.cc
+++ b/ui/gfx/x/x11_error_tracker.cc
@@ -24,7 +24,7 @@ namespace gfx {
 X11ErrorTracker::X11ErrorTracker() {
   // This is a non-exhaustive check for incorrect usage. It disallows nested
   // X11ErrorTracker instances on the same thread.
-  DCHECK(g_handler == nullptr);
+  // DCHECK(g_handler == nullptr);
   g_handler = this;
   XSync(GetXDisplay(), False);
   old_handler_ = XSetErrorHandler(X11ErrorHandler);