Fix error in debug printing from the Dart executable, introduced in r14357.

runtime/bin/builtin_natives.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/builtin.h"
 
 #include <stdlib.h>
 #include <string.h>
 
 #include "bin/dartutils.h"
@@ skipping 85 matching lines @@
     }
   }
   return NULL;
 }
 
 
 // Implementation of native functions which are used for some
 // test/debug functionality in standalone dart mode.
 
 void Builtin::PrintString(FILE* out, Dart_Handle str) {
-  intptr_t length = 0;
-  Dart_Handle result = Dart_StringLength(str, &length);
-  DART_CHECK_VALID(result);
-  uint8_t* chars = reinterpret_cast<uint8_t*>(malloc(length * sizeof(uint8_t)));
-  result = Dart_StringToUTF8(str, chars, &length);
+  const char* chars = NULL;
+
+  Dart_Handle result = Dart_StringToCString(str, &chars);
   if (Dart_IsError(result)) {
     // TODO(turnidge): Consider propagating some errors here.  What if
     // an isolate gets interrupted by the embedder in the middle of
     // Dart_StringToBytes?  We need to make sure not to swallow the
     // interrupt.
     fputs(Dart_GetError(result), out);
   } else {
+    intptr_t length = strlen(chars);
     fwrite(chars, sizeof(*chars), length, out);
   }
   fputc('\n', out);
   fflush(out);
-  free(chars);
 }
 
 
 void FUNCTION_NAME(Logger_PrintString)(Dart_NativeArguments args) {
   Dart_EnterScope();
   Builtin::PrintString(stdout, Dart_GetNativeArgument(args, 0));
   Dart_ExitScope();
 }
 
 
 void FUNCTION_NAME(Exit)(Dart_NativeArguments args) {
   Dart_EnterScope();
   int64_t status = 0;
   // Ignore result if passing invalid argument and just exit 0.
   DartUtils::GetInt64Value(Dart_GetNativeArgument(args, 0), &status);
   Dart_ExitScope();
   exit(status);
 }