diff -r 000000000000 -r 6474c204b198 dom/xslt/base/txURIUtils.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/xslt/base/txURIUtils.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,75 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "txURIUtils.h"
+#include "nsNetUtil.h"
+#include "nsIDocument.h"
+#include "nsIPrincipal.h"
+
+/**
+ * URIUtils
+ * A set of utilities for handling URIs
+**/
+
+/**
+ * Resolves the given href argument, using the given documentBase
+ * if necessary.
+ * The new resolved href will be appended to the given dest String
+**/
+void URIUtils::resolveHref(const nsAString& href, const nsAString& base,
+                           nsAString& dest) {
+    if (base.IsEmpty()) {
+        dest.Append(href);
+        return;
+    }
+    if (href.IsEmpty()) {
+        dest.Append(base);
+        return;
+    }
+    nsCOMPtr<nsIURI> pURL;
+    nsAutoString resultHref;
+    nsresult result = NS_NewURI(getter_AddRefs(pURL), base);
+    if (NS_SUCCEEDED(result)) {
+        NS_MakeAbsoluteURI(resultHref, href, pURL);
+        dest.Append(resultHref);
+    }
+} //-- resolveHref
+
+// static
+void
+URIUtils::ResetWithSource(nsIDocument *aNewDoc, nsIDOMNode *aSourceNode)
+{
+    nsCOMPtr<nsINode> node = do_QueryInterface(aSourceNode);
+    if (!node) {
+        // XXXbz passing nullptr as the first arg to Reset is illegal
+        aNewDoc->Reset(nullptr, nullptr);
+        return;
+    }
+
+    nsCOMPtr<nsIDocument> sourceDoc = node->OwnerDoc();
+    nsIPrincipal* sourcePrincipal = sourceDoc->NodePrincipal();
+
+    // Copy the channel and loadgroup from the source document.
+    nsCOMPtr<nsILoadGroup> loadGroup = sourceDoc->GetDocumentLoadGroup();
+    nsCOMPtr<nsIChannel> channel = sourceDoc->GetChannel();
+    if (!channel) {
+        // Need to synthesize one
+        if (NS_FAILED(NS_NewChannel(getter_AddRefs(channel),
+                                    sourceDoc->GetDocumentURI(),
+                                    nullptr,
+                                    loadGroup))) {
+            return;
+        }
+        channel->SetOwner(sourcePrincipal);
+    }
+    aNewDoc->Reset(channel, loadGroup);
+    aNewDoc->SetPrincipal(sourcePrincipal);
+    aNewDoc->SetBaseURI(sourceDoc->GetDocBaseURI());
+
+    // Copy charset
+    aNewDoc->SetDocumentCharacterSetSource(
+          sourceDoc->GetDocumentCharacterSetSource());
+    aNewDoc->SetDocumentCharacterSet(sourceDoc->GetDocumentCharacterSet());
+}