PPAPI: Force async callback invocation option.

ppapi/cpp/dev/file_chooser_dev.cc

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// 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.
 
 #include "ppapi/cpp/dev/file_chooser_dev.h"
 
 #include "ppapi/c/dev/ppb_file_chooser_dev.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/cpp/completion_callback.h"
 #include "ppapi/cpp/dev/file_ref_dev.h"
 #include "ppapi/cpp/instance.h"
@@ skipping 17 matching lines @@
   PassRefFromConstructor(get_interface<PPB_FileChooser_Dev>()->Create(
       instance.pp_instance(), &options));
 }
 
 FileChooser_Dev::FileChooser_Dev(const FileChooser_Dev& other)
     : Resource(other) {
 }
 
 int32_t FileChooser_Dev::Show(const CompletionCallback& cc) {
   if (!has_interface<PPB_FileChooser_Dev>())
-    return PP_ERROR_NOINTERFACE;
+    return cc.MayForce(PP_ERROR_NOINTERFACE);
   return get_interface<PPB_FileChooser_Dev>()->Show(
       pp_resource(), cc.pp_completion_callback());
 }
 
 FileRef_Dev FileChooser_Dev::GetNextChosenFile() const {
   if (!has_interface<PPB_FileChooser_Dev>())
     return FileRef_Dev();
   return FileRef_Dev(FileRef_Dev::PassRef(),
       get_interface<PPB_FileChooser_Dev>()->GetNextChosenFile(pp_resource()));
 }
 
 }  // namespace pp