diff -r 000000000000 -r 6474c204b198 intl/locale/src/nsCharsetAlias.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/intl/locale/src/nsCharsetAlias.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,84 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 "mozilla/ArrayUtils.h"
+
+#include "nsCharsetAlias.h"
+
+// for NS_ERROR_UCONV_NOCONV
+#include "nsCharsetConverterManager.h"
+
+#include "nsUConvPropertySearch.h"
+
+using namespace mozilla;
+
+// 
+static const char* kAliases[][3] = {
+#include "charsetalias.properties.h"
+};
+
+//--------------------------------------------------------------
+// static
+nsresult
+nsCharsetAlias::GetPreferredInternal(const nsACString& aAlias,
+                                     nsACString& oResult)
+{
+   nsAutoCString key(aAlias);
+   ToLowerCase(key);
+
+   return nsUConvPropertySearch::SearchPropertyValue(kAliases,
+      ArrayLength(kAliases), key, oResult);
+}
+
+//--------------------------------------------------------------
+// static
+nsresult
+nsCharsetAlias::GetPreferred(const nsACString& aAlias,
+                             nsACString& oResult)
+{
+   if (aAlias.IsEmpty()) return NS_ERROR_NULL_POINTER;
+
+   nsresult res = GetPreferredInternal(aAlias, oResult);
+   if (NS_FAILED(res))
+      return res;
+
+   if (nsCharsetConverterManager::IsInternal(oResult))
+      return NS_ERROR_UCONV_NOCONV;
+
+   return res;
+}
+
+//--------------------------------------------------------------
+// static
+nsresult
+nsCharsetAlias::Equals(const nsACString& aCharset1,
+                       const nsACString& aCharset2, bool* oResult)
+{
+   nsresult res = NS_OK;
+
+   if(aCharset1.Equals(aCharset2, nsCaseInsensitiveCStringComparator())) {
+      *oResult = true;
+      return res;
+   }
+
+   if(aCharset1.IsEmpty() || aCharset2.IsEmpty()) {
+      *oResult = false;
+      return res;
+   }
+
+   *oResult = false;
+   nsAutoCString name1;
+   res = GetPreferredInternal(aCharset1, name1);
+   if (NS_FAILED(res))
+     return res;
+
+   nsAutoCString name2;
+   res = GetPreferredInternal(aCharset2, name2);
+   if (NS_FAILED(res))
+     return res;
+
+   *oResult = name1.Equals(name2);
+   return NS_OK;
+}