PPAPI: Make blocking completion callbacks work.

ppapi/thunk/ppb_graphics_2d_thunk.cc

 // 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.
 
 #include "ppapi/c/pp_completion_callback.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/c/ppb_graphics_2d.h"
 #include "ppapi/thunk/enter.h"
 #include "ppapi/thunk/ppb_graphics_2d_api.h"
 #include "ppapi/thunk/resource_creation_api.h"
@@ skipping 52 matching lines @@
   enter.object()->Scroll(clip_rect, amount);
 }
 
 void ReplaceContents(PP_Resource graphics_2d, PP_Resource image_data) {
   EnterGraphics2D enter(graphics_2d, true);
   if (enter.failed())
     return;
   enter.object()->ReplaceContents(image_data);
 }
 
-int32_t Flush(PP_Resource graphics_2d,
-              PP_CompletionCallback callback) {
+int32_t Flush(PP_Resource graphics_2d, PP_CompletionCallback callback) {
   EnterGraphics2D enter(graphics_2d, callback, true);
   if (enter.failed())
     return enter.retval();
-  return enter.SetResult(enter.object()->Flush(callback));
+  return enter.SetResult(enter.object()->Flush(enter.callback()));
 }
 
 const PPB_Graphics2D g_ppb_graphics_2d_thunk = {
   &Create,
   &IsGraphics2D,
   &Describe,
   &PaintImageData,
   &Scroll,
   &ReplaceContents,
   &Flush
 };
 
 }  // namespace
 
 const PPB_Graphics2D_1_0* GetPPB_Graphics2D_1_0_Thunk() {
   return &g_ppb_graphics_2d_thunk;
 }
 
 }  // namespace thunk
 }  // namespace ppapi