Fix memory leaks in system string patch

runtime/bin/process.cc

 // 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.
 
 #include "bin/dartutils.h"
 #include "bin/io_buffer.h"
 #include "bin/process.h"
 #include "bin/socket.h"
 
 #include "include/dart_api.h"
@@ skipping 177 matching lines @@
   if (Dart_IsError(result)) Dart_PropagateError(result);
   uint8_t* buffer = new uint8_t[bytes_length];
   result = Dart_ListGetAsBytes(bytes, 0, buffer, bytes_length);
   if (Dart_IsError(result)) {
     delete[] buffer;
     Dart_PropagateError(result);
   }
   char* str =
       StringUtils::SystemStringToUtf8(reinterpret_cast<char*>(buffer));
   Dart_SetReturnValue(args, DartUtils::NewString(str));
+  if (str != reinterpret_cast<char*>(buffer)) free(str);
   Dart_ExitScope();
 }
 
 
 void FUNCTION_NAME(StringToSystemEncoding)(Dart_NativeArguments args) {
   Dart_EnterScope();
   Dart_Handle str = Dart_GetNativeArgument(args, 0);
   const char* utf8 = DartUtils::GetStringValue(str);
   const char* system_string = StringUtils::Utf8ToSystemString(utf8);
   int external_length = strlen(system_string);
   uint8_t* buffer = NULL;
   Dart_Handle external_array = IOBuffer::Allocate(external_length, &buffer);
   memmove(buffer, system_string, external_length);
+  if (utf8 != system_string) free(const_cast<char*>(system_string));
   Dart_SetReturnValue(args, external_array);
   Dart_ExitScope();
 }