[bootstrapper] extra natives must not use natives syntax.

src/extensions/externalize-string-extension.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/extensions/externalize-string-extension.h"
 
 #include "src/api.h"
 #include "src/handles.h"
 #include "src/isolate.h"
 
@@ skipping 18 matching lines @@
   Char* const data_;
   const size_t length_;
 };
 
 
 typedef SimpleStringResource<char, v8::String::ExternalOneByteStringResource>
     SimpleOneByteStringResource;
 typedef SimpleStringResource<uc16, v8::String::ExternalStringResource>
     SimpleTwoByteStringResource;
 
-
 const char* const ExternalizeStringExtension::kSource =
     "native function externalizeString();"
-    "native function isOneByteString();";
+    "native function isOneByteString();"
+    "function x() { return 1; }";
 
 v8::Local<v8::FunctionTemplate>
 ExternalizeStringExtension::GetNativeFunctionTemplate(
     v8::Isolate* isolate, v8::Local<v8::String> str) {
   if (strcmp(*v8::String::Utf8Value(str), "externalizeString") == 0) {
     return v8::FunctionTemplate::New(isolate,
                                      ExternalizeStringExtension::Externalize);
   } else {
     DCHECK(strcmp(*v8::String::Utf8Value(str), "isOneByteString") == 0);
     return v8::FunctionTemplate::New(isolate,
@@ skipping 80 matching lines @@
             NewStringType::kNormal).ToLocalChecked());
     return;
   }
   bool is_one_byte =
       Utils::OpenHandle(*args[0].As<v8::String>())->IsOneByteRepresentation();
   args.GetReturnValue().Set(is_one_byte);
 }
 
 }  // namespace internal
 }  // namespace v8