Fix leak of message snapshot buffer when attempting to send an illegal object.

runtime/vm/datastream.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 RUNTIME_VM_DATASTREAM_H_
 #define RUNTIME_VM_DATASTREAM_H_
 
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/allocation.h"
 #include "vm/exceptions.h"
 #include "vm/globals.h"
 #include "vm/os.h"
 
 namespace dart {
 
 static const int8_t kDataBitsPerByte = 7;
 static const int8_t kByteMask = (1 << kDataBitsPerByte) - 1;
 static const int8_t kMaxUnsignedDataPerByte = kByteMask;
 static const int8_t kMinDataPerByte = -(1 << (kDataBitsPerByte - 1));
 static const int8_t kMaxDataPerByte = (~kMinDataPerByte & kByteMask);  // NOLINT
 static const uint8_t kEndByteMarker = (255 - kMaxDataPerByte);
 static const uint8_t kEndUnsignedByteMarker = (255 - kMaxUnsignedDataPerByte);
 
 typedef uint8_t* (*ReAlloc)(uint8_t* ptr, intptr_t old_size, intptr_t new_size);
+typedef void (*DeAlloc)(uint8_t* ptr);
 
 // Stream for reading various types from a buffer.
 class ReadStream : public ValueObject {
  public:
   ReadStream(const uint8_t* buffer, intptr_t size)
       : buffer_(buffer), current_(buffer), end_(buffer + size) {}
 
   void SetStream(const uint8_t* buffer, intptr_t size) {
     buffer_ = buffer;
     current_ = buffer;
@@ skipping 413 matching lines @@
   intptr_t current_size_;
   ReAlloc alloc_;
   intptr_t initial_size_;
 
   DISALLOW_COPY_AND_ASSIGN(WriteStream);
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_DATASTREAM_H_