Bug 1738418 - set sandboxflags for object/embed loads correctly r=ckerschb,smaug,necko-reviewers

Depends on D130958

Differential Revision: https://phabricator.services.mozilla.com/D130959

dom/base/nsObjectLoadingContent.cpp

@@ -1839,6 +1839,8 @@ nsresult nsObjectLoadingContent::OpenChannel() {
     if (cspToInherit) {
       loadState->SetCsp(cspToInherit);
     }
+    loadState->SetTriggeringSandboxFlags(sandboxFlags);
+
     // TODO(djg): This was httpChan->SetReferrerInfoWithoutClone(referrerInfo);
     // Is the ...WithoutClone(...) important?
     auto referrerInfo = MakeRefPtr<ReferrerInfo>(*doc);

netwerk/ipc/DocumentLoadListener.cpp

@@ -809,7 +809,7 @@ auto DocumentLoadListener::OpenObject(
 
   MOZ_ASSERT(!mIsDocumentLoad);
 
-  auto sandboxFlags = GetLoadingBrowsingContext()->GetSandboxFlags();
+  auto sandboxFlags = aLoadState->TriggeringSandboxFlags();
 
   RefPtr<LoadInfo> loadInfo = CreateObjectLoadInfo(
       aLoadState, aInnerWindowId, aContentPolicyType, sandboxFlags);