PPAPI: Make blocking completion callbacks work.

webkit/plugins/ppapi/ppb_graphics_2d_impl.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 "webkit/plugins/ppapi/ppb_graphics_2d_impl.h"
 
 #include <iterator>
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
@@ skipping 296 matching lines @@
         "PPB_Graphics2D.ReplaceContents: Image size doesn't match "
         "Graphics2D size.");
     return;
   }
 
   QueuedOperation operation(QueuedOperation::REPLACE);
   operation.replace_image = image_resource;
   queued_operations_.push_back(operation);
 }
 
-int32_t PPB_Graphics2D_Impl::Flush(PP_CompletionCallback callback) {
+int32_t PPB_Graphics2D_Impl::Flush(scoped_refptr<TrackedCallback> callback) {
   TRACE_EVENT0("pepper", "PPB_Graphics2D_Impl::Flush");
-  if (!callback.func)
-    return PP_ERROR_BLOCKS_MAIN_THREAD;
-
   // Don't allow more than one pending flush at a time.
   if (HasPendingFlush())
     return PP_ERROR_INPROGRESS;
 
   bool nothing_visible = true;
   for (size_t i = 0; i < queued_operations_.size(); i++) {
     QueuedOperation& operation = queued_operations_[i];
     gfx::Rect op_rect;
     switch (operation.type) {
       case QueuedOperation::PAINT:
@@ skipping 35 matching lines @@
       } else {
         bound_instance_->InvalidateRect(op_rect);
       }
     }
   }
   queued_operations_.clear();
 
   if (nothing_visible) {
     // There's nothing visible to invalidate so just schedule the callback to
     // execute in the next round of the message loop.
-    ScheduleOffscreenCallback(FlushCallbackData(
-        scoped_refptr<TrackedCallback>(new TrackedCallback(this, callback))));
+    ScheduleOffscreenCallback(FlushCallbackData(callback));
   } else {
-    unpainted_flush_callback_.Set(
-        scoped_refptr<TrackedCallback>(new TrackedCallback(this, callback)));
+    unpainted_flush_callback_.Set(callback);
   }
   return PP_OK_COMPLETIONPENDING;
 }
 
 bool PPB_Graphics2D_Impl::ReadImageData(PP_Resource image,
                                         const PP_Point* top_left) {
   // Get and validate the image object to paint into.
   EnterResourceNoLock<PPB_ImageData_API> enter(image, true);
   if (enter.failed())
     return false;
@@ skipping 293 matching lines @@
 }
 
 bool PPB_Graphics2D_Impl::HasPendingFlush() const {
   return !unpainted_flush_callback_.is_null() ||
          !painted_flush_callback_.is_null() ||
          offscreen_flush_pending_;
 }
 
 }  // namespace ppapi
 }  // namespace webkit