Implement asynchronous interface/plumbing for GetDefaultPrintSettings.

ppapi/thunk/ppb_instance_api.h

 // Copyright (c) 2012 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_THUNK_INSTANCE_API_H_
 #define PPAPI_THUNK_INSTANCE_API_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "ppapi/c/dev/pp_print_settings_dev.h"
@@ skipping 98 matching lines @@
                             PP_MouseCursor_Type type,
                             PP_Resource image,
                             const PP_Point* hot_spot) = 0;
 
   // MouseLock.
   virtual int32_t LockMouse(PP_Instance instance,
                             scoped_refptr<TrackedCallback> callback) = 0;
   virtual void UnlockMouse(PP_Instance instance) = 0;
 
   // Printing.
-  virtual PP_Bool GetDefaultPrintSettings(
+  virtual int32_t GetDefaultPrintSettings(
       PP_Instance instance,
-      PP_PrintSettings_Dev* print_settings) = 0;
+      PP_PrintSettings_Dev* print_settings,
+      scoped_refptr<TrackedCallback> callback) = 0;
 
   // TextInput.
   virtual void SetTextInputType(PP_Instance instance,
                                 PP_TextInput_Type type) = 0;
   virtual void UpdateCaretPosition(PP_Instance instance,
                                    const PP_Rect& caret,
                                    const PP_Rect& bounding_box) = 0;
   virtual void CancelCompositionText(PP_Instance instance) = 0;
   virtual void SelectionChanged(PP_Instance instance) = 0;
   virtual void UpdateSurroundingText(PP_Instance instance,
@@ skipping 21 matching lines @@
                                       PP_URLComponents_Dev* components) = 0;
 #endif  // !defined(OS_NACL)
 
   static const ApiID kApiID = API_ID_PPB_INSTANCE;
 };
 
 }  // namespace thunk
 }  // namespace ppapi
 
 #endif  // PPAPI_THUNK_INSTANCE_API_H_