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

patches/chromium/expose-net-observer-api.patch

@@ -0,0 +1,29 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jeremy Apthorp <jeremya@chromium.org>
+Date: Thu, 18 Oct 2018 17:06:56 -0700
+Subject: expose-net-observer-api.patch
+
+Expose URLRequestContextGetter::{Add,Remove}Observer.
+This patch should be removed once we switch to using the net service (cc @robo)
+
+diff --git a/net/url_request/url_request_context_getter.h b/net/url_request/url_request_context_getter.h
+index def76d3902f30ae1384ae5f629fa116b3975fa86..e5ee0bfa93f497f18bdb3ad7cd51a6726dc87f3e 100644
+--- a/net/url_request/url_request_context_getter.h
++++ b/net/url_request/url_request_context_getter.h
+@@ -79,11 +79,16 @@ class NET_EXPORT URLRequestContextGetter
+   friend class web::NetworkContextOwner;
+ #endif  // defined(OS_IOS)
+ 
++  // NOTE(nornagon/robo): electron currently depends on this deprecated API
++  // from net/, but will be removing it soon when we switch to using the
++  // network service.
++ public:
+   // Adds / removes an observer to watch for shutdown of |this|'s context. Must
+   // only be called on network thread. May not be called once
+   // GetURLRequestContext() starts returning nullptr.
+   void AddObserver(URLRequestContextGetterObserver* observer);
+   void RemoveObserver(URLRequestContextGetterObserver* observer);
++ private:
+ 
+   // OnDestruct is used to ensure deletion on the thread on which the request
+   // IO happens.