--- a/intl/uconv/nsTextToSubURI.cpp
+++ b/intl/uconv/nsTextToSubURI.cpp
@@ -165,52 +165,47 @@ static bool statefulCharset(const char *
       !nsCRT::strcasecmp(charset, "HZ-GB-2312"))
     return true;
 
   return false;
 }
 
 nsresult nsTextToSubURI::convertURItoUnicode(const nsAFlatCString &aCharset,
                                              const nsAFlatCString &aURI, 
-                                             bool aIRI, 
                                              nsAString &_retval)
 {
-  nsresult rv = NS_OK;
-
   // check for 7bit encoding the data may not be ASCII after we decode
   bool isStatefulCharset = statefulCharset(aCharset.get());
 
-  if (!isStatefulCharset && IsASCII(aURI)) {
-    CopyASCIItoUTF16(aURI, _retval);
-    return rv;
-  }
-
-  if (!isStatefulCharset && aIRI) {
+  if (!isStatefulCharset) {
+    if (IsASCII(aURI)) {
+      CopyASCIItoUTF16(aURI, _retval);
+      return NS_OK;
+    }
     if (IsUTF8(aURI)) {
       CopyUTF8toUTF16(aURI, _retval);
-      return rv;
+      return NS_OK;
     }
   }
 
   // empty charset could indicate UTF-8, but aURI turns out not to be UTF-8.
   NS_ENSURE_FALSE(aCharset.IsEmpty(), NS_ERROR_INVALID_ARG);
 
   nsAutoCString encoding;
   if (!EncodingUtils::FindEncodingForLabelNoReplacement(aCharset, encoding)) {
     return NS_ERROR_UCONV_NOCONV;
   }
   nsCOMPtr<nsIUnicodeDecoder> unicodeDecoder =
     EncodingUtils::DecoderForEncoding(encoding);
 
-  NS_ENSURE_SUCCESS(rv, rv);
   unicodeDecoder->SetInputErrorBehavior(nsIUnicodeDecoder::kOnError_Signal);
 
   int32_t srcLen = aURI.Length();
   int32_t dstLen;
-  rv = unicodeDecoder->GetMaxLength(aURI.get(), srcLen, &dstLen);
+  nsresult rv = unicodeDecoder->GetMaxLength(aURI.get(), srcLen, &dstLen);
   NS_ENSURE_SUCCESS(rv, rv);
 
   char16_t *ustr = (char16_t *) NS_Alloc(dstLen * sizeof(char16_t));
   NS_ENSURE_TRUE(ustr, NS_ERROR_OUT_OF_MEMORY);
 
   rv = unicodeDecoder->Convert(aURI.get(), &srcLen, ustr, &dstLen);
 
   if (NS_SUCCEEDED(rv))
@@ -229,23 +224,23 @@ NS_IMETHODIMP  nsTextToSubURI::UnEscapeU
   // skip control octets (0x00 - 0x1f and 0x7f) when unescaping
   NS_UnescapeURL(PromiseFlatCString(aURIFragment), 
                  esc_SkipControl | esc_AlwaysCopy, unescapedSpec);
 
   // in case of failure, return escaped URI
   // Test for != NS_OK rather than NS_FAILED, because incomplete multi-byte
   // sequences are also considered failure in this context
   if (convertURItoUnicode(
-                PromiseFlatCString(aCharset), unescapedSpec, true, _retval)
+                PromiseFlatCString(aCharset), unescapedSpec, _retval)
       != NS_OK) {
     // assume UTF-8 instead of ASCII  because hostname (IDN) may be in UTF-8
     CopyUTF8toUTF16(aURIFragment, _retval);
   }
 
-  // if there are any characters that are unsafe for IRIs, reescape.
+  // If there are any characters that are unsafe for URIs, reescape those.
   if (mUnsafeChars.IsEmpty()) {
     nsCOMPtr<nsISupportsString> blacklist;
     nsresult rv = mozilla::Preferences::GetComplex("network.IDN.blacklist_chars",
                                                    NS_GET_IID(nsISupportsString),
                                                    getter_AddRefs(blacklist));
     if (NS_SUCCEEDED(rv)) {
       nsString chars;
       blacklist->ToString(getter_Copies(chars));
@@ -284,12 +279,12 @@ NS_IMETHODIMP  nsTextToSubURI::UnEscapeN
        aCharset.LowerCaseEqualsLiteral("utf-16be") ||
        aCharset.LowerCaseEqualsLiteral("utf-16le") ||
        aCharset.LowerCaseEqualsLiteral("utf-7") ||
        aCharset.LowerCaseEqualsLiteral("x-imap4-modified-utf7"))){
     CopyASCIItoUTF16(aURIFragment, _retval);
     return NS_OK;
   }
 
-  return convertURItoUnicode(PromiseFlatCString(aCharset), unescapedSpec, true, _retval);
+  return convertURItoUnicode(PromiseFlatCString(aCharset), unescapedSpec, _retval);
 }
 
 //----------------------------------------------------------------------

--- a/intl/uconv/nsTextToSubURI.h
+++ b/intl/uconv/nsTextToSubURI.h
@@ -1,40 +1,31 @@
-/* -*- Mode: C; tab-width: 4; 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/. */
+// -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+// vim: set ts=2 et sw=2 tw=80:
+// This Source Code is subject to the terms of the Mozilla Public License
+// version 2.0 (the "License"). You can obtain a copy of the License at
+// http://mozilla.org/MPL/2.0/.
 #ifndef nsTextToSubURI_h__
 #define nsTextToSubURI_h__
 
 #include "nsITextToSubURI.h"
 #include "nsString.h"
 #include "nsTArray.h"
 
-//==============================================================
-class nsTextToSubURI: public nsITextToSubURI {
+class nsTextToSubURI: public nsITextToSubURI
+{
   NS_DECL_ISUPPORTS
   NS_DECL_NSITEXTTOSUBURI
 
 private:
   virtual ~nsTextToSubURI();
 
-  // IRI is "Internationalized Resource Identifiers"
-  // http://www.ietf.org/internet-drafts/draft-duerst-iri-01.txt
-  // 
-  // if the IRI option is true then we assume that the URI is encoded as UTF-8
-  // note: there is no definite way to distinguish between IRI and a URI encoded 
-  // with a non-UTF-8 charset
-  // Use this option carefully -- it may cause dataloss
-  // (recommended to set to true for UI purpose only)
-  //
+  // We assume that the URI is encoded as UTF-8.
   nsresult convertURItoUnicode(const nsAFlatCString &aCharset,
                                const nsAFlatCString &aURI, 
-                               bool aIRI, 
                                nsAString &_retval);
 
   // Characters from the pref "network.IDN.blacklist_chars", or a built-in
   // fallback if reading the pref fails.
   nsTArray<char16_t> mUnsafeChars;
 };
 
 #endif // nsTextToSubURI_h__
-