Mark deprecated APIs with relatively little use as deprecated

src/extensions/externalize-string-extension.h

Index: src/extensions/externalize-string-extension.h
diff --git a/src/extensions/externalize-string-extension.h b/src/extensions/externalize-string-extension.h
index ecbc1cf447c47ac5c99262371c0950b7eae35267..3d1e438f7f2617b806ccf25ee96f4b6eb0729284 100644
--- a/src/extensions/externalize-string-extension.h
+++ b/src/extensions/externalize-string-extension.h
@@ -36,7 +36,8 @@ namespace internal {
 class ExternalizeStringExtension : public v8::Extension {
  public:
   ExternalizeStringExtension() : v8::Extension("v8/externalize", kSource) {}
-  virtual v8::Handle<v8::FunctionTemplate> GetNativeFunction(
+  virtual v8::Handle<v8::FunctionTemplate> GetNativeFunctionTemplate(
+      v8::Isolate* isolate,
       v8::Handle<v8::String> name);
   static void Externalize(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void IsAscii(const v8::FunctionCallbackInfo<v8::Value>& args);