Bug 1744611 - Clear-Site-Data: "cache": Also clear CSS and Image cache r=emilio,anti-tracking-reviewers,timhuang

This changes principal in CSS-/Image-cache to use partitionedPrincipal
to match the caller side from `Clear-Site-Data: "cache"`.

Differential Revision: https://phabricator.services.mozilla.com/D254379

Author: mb

layout/style/SharedSubResourceCache.cpp

@@ -106,7 +106,7 @@ bool ShouldClearEntry(nsIURI* aEntryURI, nsIPrincipal* aEntryLoaderPrincipal,
     return spec == *aURL;
   }
 
-  if (aPrincipal && aEntryLoaderPrincipal->Equals(aPrincipal.ref())) {
+  if (aPrincipal && aEntryPartitionPrincipal->Equals(aPrincipal.ref())) {
     return true;
   }
   if (!aSchemelessSite) {