diff --git a/dom/media/eme/mediafoundation/WMFCDMImpl.cpp b/dom/media/eme/mediafoundation/WMFCDMImpl.cpp
index 0af18f9aebfe..2192e976c104 100644
--- a/dom/media/eme/mediafoundation/WMFCDMImpl.cpp
+++ b/dom/media/eme/mediafoundation/WMFCDMImpl.cpp
@@ -15,6 +15,24 @@ include
 "
 mozilla
 /
+AppShutdown
+.
+h
+"
+#
+include
+"
+mozilla
+/
+ClearOnShutdown
+.
+h
+"
+#
+include
+"
+mozilla
+/
 dom
 /
 MediaKeySession
@@ -47,6 +65,31 @@ nsAString
 aKeySystem
 )
 {
+MOZ_ASSERT
+(
+NS_IsMainThread
+(
+)
+)
+;
+if
+(
+AppShutdown
+:
+:
+IsInOrBeyond
+(
+ShutdownPhase
+:
+:
+AppShutdownConfirmed
+)
+)
+{
+return
+false
+;
+}
 static
 std
 :
@@ -56,8 +99,67 @@ map
 nsString
 bool
 >
-supports
+sSupports
+;
+static
+bool
+sSetRunOnShutdown
+=
+false
 ;
+if
+(
+!
+sSetRunOnShutdown
+)
+{
+GetMainThreadSerialEventTarget
+(
+)
+-
+>
+Dispatch
+(
+NS_NewRunnableFunction
+(
+"
+WMFCDMImpl
+:
+:
+Supports
+"
+[
+&
+]
+{
+RunOnShutdown
+(
+[
+&
+]
+{
+sSupports
+.
+clear
+(
+)
+;
+}
+ShutdownPhase
+:
+:
+XPCOMShutdown
+)
+;
+}
+)
+)
+;
+sSetRunOnShutdown
+=
+true
+;
+}
 nsString
 key
 (
@@ -71,7 +173,7 @@ auto
 &
 s
 =
-supports
+sSupports
 .
 find
 (
@@ -81,7 +183,7 @@ key
 s
 !
 =
-supports
+sSupports
 .
 end
 (
@@ -126,7 +228,7 @@ GetCapabilities
 configs
 )
 ;
-supports
+sSupports
 [
 key
 ]
@@ -151,21 +253,31 @@ KeySystemConfig
 aOutConfigs
 )
 {
-nsCOMPtr
-<
-nsISerialEventTarget
->
-backgroundTaskQueue
+MOZ_ASSERT
+(
+NS_IsMainThread
+(
+)
+)
 ;
-NS_CreateBackgroundTaskQueue
+if
 (
-__func__
-getter_AddRefs
+AppShutdown
+:
+:
+IsInOrBeyond
 (
-backgroundTaskQueue
+ShutdownPhase
+:
+:
+AppShutdownConfirmed
 )
 )
+{
+return
+false
 ;
+}
 static
 std
 :
@@ -185,6 +297,65 @@ sKeySystemConfigs
 {
 }
 ;
+static
+bool
+sSetRunOnShutdown
+=
+false
+;
+if
+(
+!
+sSetRunOnShutdown
+)
+{
+GetMainThreadSerialEventTarget
+(
+)
+-
+>
+Dispatch
+(
+NS_NewRunnableFunction
+(
+"
+WMFCDMImpl
+:
+:
+GetCapabilities
+"
+[
+&
+]
+{
+RunOnShutdown
+(
+[
+&
+]
+{
+sKeySystemConfigs
+.
+clear
+(
+)
+;
+}
+ShutdownPhase
+:
+:
+XPCOMShutdown
+)
+;
+}
+)
+)
+;
+sSetRunOnShutdown
+=
+true
+;
+}
 auto
 keySystem
 =
@@ -292,6 +463,21 @@ return
 true
 ;
 }
+nsCOMPtr
+<
+nsISerialEventTarget
+>
+backgroundTaskQueue
+;
+NS_CreateBackgroundTaskQueue
+(
+__func__
+getter_AddRefs
+(
+backgroundTaskQueue
+)
+)
+;
 if
 (
 !