PPAPI: Make blocking completion callbacks work.

ppapi/proxy/ppb_graphics_2d_proxy.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/proxy/ppb_graphics_2d_proxy.h"
 
 #include <string.h>  // For memset.
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
@@ skipping 25 matching lines @@
   virtual PPB_Graphics2D_API* AsPPB_Graphics2D_API();
 
   // PPB_Graphics_2D_API.
   PP_Bool Describe(PP_Size* size, PP_Bool* is_always_opaque);
   void PaintImageData(PP_Resource image_data,
                       const PP_Point* top_left,
                       const PP_Rect* src_rect);
   void Scroll(const PP_Rect* clip_rect,
               const PP_Point* amount);
   void ReplaceContents(PP_Resource image_data);
-  int32_t Flush(PP_CompletionCallback callback);
+  int32_t Flush(scoped_refptr<TrackedCallback> callback);
 
   // Notification that the host has sent an ACK for a pending Flush.
   void FlushACK(int32_t result_code);
 
  private:
   PluginDispatcher* GetDispatcher() const {
     return PluginDispatcher::GetForResource(this);
   }
 
   static const ApiID kApiID = API_ID_PPB_GRAPHICS_2D;
@@ skipping 62 matching lines @@
   if (!image_object || pp_instance() != image_object->pp_instance()) {
     Log(PP_LOGLEVEL_ERROR,
         "PPB_Graphics2D.PaintImageData: Bad image resource.");
     return;
   }
 
   GetDispatcher()->Send(new PpapiHostMsg_PPBGraphics2D_ReplaceContents(
       kApiID, host_resource(), image_object->host_resource()));
 }
 
-int32_t Graphics2D::Flush(PP_CompletionCallback callback) {
-  // For now, disallow blocking calls. We'll need to add support for other
-  // threads to this later.
-  if (!callback.func)
-    return PP_ERROR_BLOCKS_MAIN_THREAD;
-
+int32_t Graphics2D::Flush(scoped_refptr<TrackedCallback> callback) {
   if (TrackedCallback::IsPending(current_flush_callback_))
     return PP_ERROR_INPROGRESS;  // Can't have >1 flush pending.
-  current_flush_callback_ = new TrackedCallback(this, callback);
+  current_flush_callback_ = callback;
 
   GetDispatcher()->Send(new PpapiHostMsg_PPBGraphics2D_Flush(kApiID,
                                                              host_resource()));
   return PP_OK_COMPLETIONPENDING;
 }
 
 void Graphics2D::FlushACK(int32_t result_code) {
   TrackedCallback::ClearAndRun(&current_flush_callback_, result_code);
 }
 
@@ skipping 106 matching lines @@
 
 void PPB_Graphics2D_Proxy::SendFlushACKToPlugin(
     int32_t result,
     const HostResource& graphics_2d) {
   dispatcher()->Send(new PpapiMsg_PPBGraphics2D_FlushACK(kApiID, graphics_2d,
                                                          result));
 }
 
 }  // namespace proxy
 }  // namespace ppapi