Bug 1954597 - Part 6: Succeed ValidatePrincipal during XPCOM shutdown, r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D242423

dom/ipc/ProcessIsolation.cpp

@@ -6,6 +6,7 @@
 
 #include "mozilla/dom/ProcessIsolation.h"
 
+#include "mozilla/AppShutdown.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/dom/BrowsingContextGroup.h"
 #include "mozilla/dom/CanonicalBrowsingContext.h"
@@ -1178,6 +1179,12 @@ bool ValidatePrincipalCouldPotentiallyBeLoadedBy(
     return aOptions.contains(ValidatePrincipalOptions::AllowSystem);
   }
 
+  // Performing checks against the remote type requires the IOService and
+  // ThirdPartyService to be available, check we're not late in shutdown.
+  if (AppShutdown::IsInOrBeyond(ShutdownPhase::XPCOMShutdownFinal)) {
+    return true;
+  }
+
   // We can load a `resource://` URI in any process. This usually comes up due
   // to pdf.js and the JSON viewer. See bug 1686200.
   if (aPrincipal->SchemeIs("resource")) {