Bug 494217 - nsINetUtil::unescapeString drops high bytes of UTF-16 strings from JS

This fixes an issue where unescapeString will drop the high bytes of a UTF-16
string when unescaping, resulting in a loss of data.
r=bz
sr=bz

netwerk/base/public/nsINetUtil.idl

@@ -46,7 +46,7 @@ interface nsIPrefBranch;
 /**
  * nsINetUtil provides various network-related utility methods.
  */
-[scriptable, uuid(57322c6f-f4ec-4e46-8253-b74be220de16)]
+[scriptable, uuid(a50d5516-5c0a-4f08-b427-703ca0c44ac3)]
 interface nsINetUtil : nsISupports
 {
   /**
@@ -192,7 +192,7 @@ interface nsINetUtil : nsISupports
    *               unescaped
    * @return unescaped string
    */
-  ACString unescapeString(in ACString aStr, in unsigned long aFlags);
+  ACString unescapeString(in AUTF8String aStr, in unsigned long aFlags);
 
   /**
    * Extract the charset parameter location and value from a content-type

netwerk/test/unit/test_unescapestring.js

@@ -13,7 +13,9 @@ var tests = [
   ["foo%ffbar", "foo\xffbar", 0],
   ["%00%1b%20%61%7f%80%ff", "%00%1b%20%61%7f\x80\xff", ONLY_NONASCII],
   ["%00%1b%20%61%7f%80%ff", "%00%1b a%7f\x80\xff", SKIP_CONTROL],
-  ["%00%1b%20%61%7f%80%ff", "%00%1b%20%61%7f\x80\xff", ONLY_NONASCII|SKIP_CONTROL]
+  ["%00%1b%20%61%7f%80%ff", "%00%1b%20%61%7f\x80\xff", ONLY_NONASCII|SKIP_CONTROL],
+  // Test that we do not drop the high-bytes of a UTF-16 string.
+  ["\u30a8\u30c9", "\xe3\x82\xa8\xe3\x83\x89", 0],
 ];
 
 function run_test() {