Backed out changeset a28aa86d1ffe (bug 1354349)

dom/ipc/ContentParent.cpp

@@ -5035,10 +5035,27 @@ ContentParent::TransmitPermissionsFor(nsIChannel* aChannel)
 {
   MOZ_ASSERT(aChannel);
 #ifdef MOZ_PERMISSIONS
+  // Check if this channel is going to be used to create a document. If it has
+  // LOAD_DOCUMENT_URI set it is trivially creating a document. If
+  // LOAD_HTML_OBJECT_DATA is set it may or may not be used to create a
+  // document, depending on its MIME type.
+  nsLoadFlags loadFlags;
+  nsresult rv = aChannel->GetLoadFlags(&loadFlags);
+  NS_ENSURE_SUCCESS(rv, rv);
 
-  nsresult rv;
-  if (!aChannel->IsDocument()) {
-    return NS_OK;
+  if (!(loadFlags & nsIChannel::LOAD_DOCUMENT_URI)) {
+    if (loadFlags & nsIRequest::LOAD_HTML_OBJECT_DATA) {
+      nsAutoCString mimeType;
+      aChannel->GetContentType(mimeType);
+      if (nsContentUtils::HtmlObjectContentTypeForMIMEType(mimeType, nullptr) !=
+          nsIObjectLoadingContent::TYPE_DOCUMENT) {
+        // The MIME type would not cause the creation of a document
+        return NS_OK;
+      }
+    } else {
+      // neither flag was set
+      return NS_OK;
+    }
   }
 
   // Get the principal for the channel result, so that we can get the permission