Do not externalize Dart strings as C strings for "print()".

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 86 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) {
-  const char* cstring = NULL;
-  Dart_Handle result = Dart_StringToCString(str, &cstring);
+  const uint8_t* characters = NULL;
+  intptr_t length;
+  Dart_Handle result = Dart_StringToBytes(str, &characters, &length);
   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_StringToCString?  We need to make sure not to swallow the
+    // Dart_StringToBytes?  We need to make sure not to swallow the
     // interrupt.
-    cstring = Dart_GetError(result);
+    fputs(Dart_GetError(result));
+  } else {
+    fwrite(characters, sizeof(*characters), length, out);
   }
-  fprintf(out, "%s\n", cstring);
+  fputc('\n', out);
   fflush(out);
 }
 
 
 void FUNCTION_NAME(Logger_PrintString)(Dart_NativeArguments args) {
   Dart_EnterScope();
   Builtin::PrintString(stdout, Dart_GetNativeArgument(args, 0));
   Dart_ExitScope();
 }
 
@@ skipping 12 matching lines @@
   } else {
     ASSERT(id == Builtin::kIOLibrary);
     url = Dart_NewString(DartUtils::kIOLibURL);
   }
   Dart_Handle builtin_lib = Dart_LookupLibrary(url);
   DART_CHECK_VALID(builtin_lib);
   // Setup the native resolver for built in library functions.
   Dart_Handle result = Dart_SetNativeResolver(builtin_lib, NativeLookup);
   DART_CHECK_VALID(result);
 }