Add support for surrogates when serializing and deserializing for native ports

runtime/vm/object.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_OBJECT_H_
 #define VM_OBJECT_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
@@ skipping 3707 matching lines @@
 
     CodePointIterator(const String& str, intptr_t start, intptr_t length)
         : str_(str),
           ch_(0),
           index_(start - 1),
           end_(start + length) {
       ASSERT(start >= 0);
       ASSERT(end_ <= str.Length());
     }
 
-    int32_t Current() {
+    int32_t Current() const {
       ASSERT(index_ >= 0);
       ASSERT(index_ < end_);
       return ch_;
     }
 
     bool Next();
 
    private:
     const String& str_;
     int32_t ch_;
@@ skipping 2234 matching lines @@
     if (this->CharAt(i) != str.CharAt(begin_index + i)) {
       return false;
     }
   }
   return true;
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_