Preserve the contents of Dart strings with unmatched surrogate halfs by avoiding a UTF16 -> UTF8

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 5574 matching lines @@
   }
 
   bool IsExternal() const {
     return RawObject::IsExternalStringClassId(raw()->GetClassId());
   }
 
   void* GetPeer() const;
 
   void ToUTF8(uint8_t* utf8_array, intptr_t array_len) const;
 
-  // Creates a UTF-8, NUL-terminated string in the current zone. The size of the
-  // created string in UTF-8 code units (bytes) is answered in 'length'; this
-  // can be longer than strlen of the result when the string has internal NULs.
-  // For the truncating version, 'max_length' is in UTF-16 code units, and will
-  // be rounded down if necessary to prevent splitting a surrogate pair.
-  const char* ToCString(intptr_t *length) const;
-  const char* ToCStringTruncated(intptr_t max_len,
-                                 bool* did_truncate,
-                                 intptr_t *length) const;
-
   // Copies the string characters into the provided external array
   // and morphs the string object into an external string object.
   // The remaining unused part of the original string object is marked as
   // an Array object or a regular Object so that it can be traversed during
   // garbage collection.
   RawString* MakeExternal(void* array,
                           intptr_t length,
                           void* peer,
                           Dart_PeerFinalizer cback) const;
 
@@ skipping 1846 matching lines @@
 
 
 RawObject* MegamorphicCache::GetTargetFunction(const Array& array,
                                                intptr_t index) {
   return array.At((index * kEntryLength) + kTargetFunctionIndex);
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_