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

patches/chromium/chrome_key_systems.patch

@@ -0,0 +1,37 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: deepak1556 <hop2deep@gmail.com>
+Date: Thu, 20 Sep 2018 17:50:13 -0700
+Subject: chrome_key_systems.patch
+
+Disable persiste licence support check for widevine cdm,
+as its not supported in the current version of chrome.
+
+diff --git a/chrome/renderer/media/chrome_key_systems.cc b/chrome/renderer/media/chrome_key_systems.cc
+index 0ef05eceaa0e42710c6cfa8acb2174cf930f6114..e0356f615f8bae10b5030f038057be027491f96c 100644
+--- a/chrome/renderer/media/chrome_key_systems.cc
++++ b/chrome/renderer/media/chrome_key_systems.cc
+@@ -15,7 +15,9 @@
+ #include "base/strings/string_split.h"
+ #include "base/strings/utf_string_conversions.h"
+ #include "build/build_config.h"
++#if 0
+ #include "chrome/renderer/chrome_render_thread_observer.h"
++#endif
+ #include "components/cdm/renderer/external_clear_key_key_system_properties.h"
+ #include "components/cdm/renderer/widevine_key_system_properties.h"
+ #include "content/public/renderer/render_thread.h"
+@@ -194,12 +196,14 @@ static SupportedCodecs GetSupportedCodecs(
+ // Returns persistent-license session support.
+ static EmeSessionTypeSupport GetPersistentLicenseSupport(
+     bool supported_by_the_cdm) {
++#if 0
+   // Do not support persistent-license if the process cannot persist data.
+   // TODO(crbug.com/457487): Have a better plan on this. See bug for details.
+   if (ChromeRenderThreadObserver::is_incognito_process()) {
+     DVLOG(2) << __func__ << ": Not supported in incognito process.";
+     return EmeSessionTypeSupport::NOT_SUPPORTED;
+   }
++#endif
+ 
+   if (!supported_by_the_cdm) {
+     DVLOG(2) << __func__ << ": Not supported by the CDM.";