ppapi: fix outdated comment in cpp header.

ppapi/cpp/completion_callback.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PPAPI_CPP_COMPLETION_CALLBACK_H_
 #define PPAPI_CPP_COMPLETION_CALLBACK_H_
 
 #include "ppapi/c/pp_completion_callback.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/cpp/logging.h"
@@ skipping 175 matching lines @@
 
   // Methods for allocating new, single-use CompletionCallbacks.
   // The CompletionCallback must be run in order for the memory
   // allocated by the methods to be freed.
   // NewRequiredCallback() creates callbacks that will always run.
   // NewOptionalCallback() creates callbacks that might not run if the method
   // taking them can complete synchronously. Thus, if after passing the
   // CompletionCallback to a PPAPI method, the method does not return
   // PP_OK_COMPLETIONPENDING, then you should manually call the
   // CompletionCallback's Run method, or memory will be leaked.
-  // NewCallback() is equivalent to NewOptionalCallback().
-  // TODO(polina): update this comment when this is no longer true.
+  // NewCallback() is equivalent to NewRequiredCallback().
 
   template <typename Method>
   CompletionCallback NewCallback(Method method) {
     PP_DCHECK(object_);
     return NewCallbackHelper(Dispatcher0<Method>(method));
   }
 
   template <typename Method>
   CompletionCallback NewRequiredCallback(Method method) {
     CompletionCallback cc = NewCallback(method);
@@ skipping 186 matching lines @@
   CompletionCallbackFactory(const CompletionCallbackFactory&);
   CompletionCallbackFactory& operator=(const CompletionCallbackFactory&);
 
   T* object_;
   BackPointer* back_pointer_;
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_COMPLETION_CALLBACK_H_