Bug 1344555 - Make nsTSubstring::Split a const method. r=gcp

xpcom/string/nsTSubstring.cpp

@@ -1106,7 +1106,8 @@ nsTSubstring_CharT::SizeOfIncludingThisEvenIfShared(
   return aMallocSizeOf(this) + SizeOfExcludingThisEvenIfShared(aMallocSizeOf);
 }
 
-nsTSubstringSplitter_CharT nsTSubstring_CharT::Split(const nsTSubstring_CharT::char_type aChar)
+nsTSubstringSplitter_CharT
+nsTSubstring_CharT::Split(const nsTSubstring_CharT::char_type aChar) const
 {
   return nsTSubstringSplitter_CharT(this, aChar);
 }

xpcom/string/nsTSubstring.h

@@ -713,7 +713,7 @@ public:
     Replace(aCutStart, aCutLength, char_traits::sEmptyBuffer, 0);
   }
 
-  nsTSubstringSplitter_CharT Split(const char_type aChar);
+  nsTSubstringSplitter_CharT Split(const char_type aChar) const;
 
   /**
    * buffer sizing