diff --git a/content/base/public/nsIContent.h b/content/base/public/nsIContent.h
index e2114beb864..e58568d8563 100644
--- a/content/base/public/nsIContent.h
+++ b/content/base/public/nsIContent.h
@@ -556,7 +556,8 @@ public:
   /**
    * Get the base URI for any relative URIs within this piece of
    * content. Generally, this is the document's base URI, but certain
-   * content carries a local base for backward compatibility.
+   * content carries a local base for backward compatibility, and XML
+   * supports setting a per-node base URI.
    *
    * @return the base URI
    */
diff --git a/content/base/src/nsFrameLoader.cpp b/content/base/src/nsFrameLoader.cpp
index a5a169ad600..7bb1c43a299 100644
--- a/content/base/src/nsFrameLoader.cpp
+++ b/content/base/src/nsFrameLoader.cpp
@@ -108,15 +108,13 @@ nsFrameLoader::LoadFrame()
     src.AssignLiteral("about:blank");
   }
 
-  // Make an absolute URI
-  nsIURI *base_uri = doc->GetBaseURI();
-
-  const nsACString &doc_charset = doc->GetDocumentCharacterSet();
+  nsCOMPtr<nsIURI> base_uri = mOwnerContent->GetBaseURI();
+  const nsAFlatCString &doc_charset = doc->GetDocumentCharacterSet();
 
   nsCOMPtr<nsIURI> uri;
   rv = NS_NewURI(getter_AddRefs(uri), src,
-                 doc_charset.IsEmpty() ? nsnull :
-                 PromiseFlatCString(doc_charset).get(), base_uri);
+                 doc_charset.IsEmpty() ? nsnull : doc_charset.get(),
+                 base_uri);
   NS_ENSURE_SUCCESS(rv, rv);
 
   nsCOMPtr<nsIDocShellLoadInfo> loadInfo;