chore: remove mips64el patches as they've largely been upstreamed (#18628)

patches/chromium/allow_nested_error_trackers.patch

@@ -0,0 +1,34 @@
+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 af031de356c5e0938fd3b84a494e48dc9a0e0476..2a5c18dc473a4f88fc0427bec69142917159bbd9 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 == NULL);
++  // DCHECK(g_handler == NULL);
+   g_handler = this;
+   XSync(GetXDisplay(), False);
+   old_handler_ = XSetErrorHandler(X11ErrorHandler);