Update ICU to 58.1

source/common/unicode/idna.h

Index: source/common/unicode/idna.h
diff --git a/source/common/unicode/idna.h b/source/common/unicode/idna.h
index 90194a378f38255b81980838b8fc384220b583b6..23a1d7ca0e84411646a5971cf0542c6e172b3cf5 100644
--- a/source/common/unicode/idna.h
+++ b/source/common/unicode/idna.h
@@ -1,3 +1,5 @@
+// Copyright (C) 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
 /*
 *******************************************************************************
 *   Copyright (C) 2010-2012, International Business Machines
@@ -198,7 +200,7 @@ public:
      * @stable ICU 4.6
      */
     virtual void
-    labelToASCII_UTF8(const StringPiece &label, ByteSink &dest,
+    labelToASCII_UTF8(StringPiece label, ByteSink &dest,
                       IDNAInfo &info, UErrorCode &errorCode) const;
 
     /**
@@ -216,7 +218,7 @@ public:
      * @stable ICU 4.6
      */
     virtual void
-    labelToUnicodeUTF8(const StringPiece &label, ByteSink &dest,
+    labelToUnicodeUTF8(StringPiece label, ByteSink &dest,
                        IDNAInfo &info, UErrorCode &errorCode) const;
 
     /**
@@ -234,7 +236,7 @@ public:
      * @stable ICU 4.6
      */
     virtual void
-    nameToASCII_UTF8(const StringPiece &name, ByteSink &dest,
+    nameToASCII_UTF8(StringPiece name, ByteSink &dest,
                      IDNAInfo &info, UErrorCode &errorCode) const;
 
     /**
@@ -252,7 +254,7 @@ public:
      * @stable ICU 4.6
      */
     virtual void
-    nameToUnicodeUTF8(const StringPiece &name, ByteSink &dest,
+    nameToUnicodeUTF8(StringPiece name, ByteSink &dest,
                       IDNAInfo &info, UErrorCode &errorCode) const;
 };