cc: Send all begin frames using a PostTask.

cc/test/pixel_test_delegating_output_surface.cc

 // Copyright 2016 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 "cc/test/pixel_test_delegating_output_surface.h"
 
 #include <stdint.h>
 #include <memory>
 #include <utility>
 
@@ skipping 70 matching lines @@
         std::move(display_context_provider_), nullptr, flipped_output_surface);
   }
   output_surface->set_surface_expansion_size(surface_expansion_size_);
 
   auto* task_runner = base::ThreadTaskRunnerHandle::Get().get();
   CHECK(task_runner);
 
   std::unique_ptr<SyntheticBeginFrameSource> begin_frame_source;
   std::unique_ptr<DisplayScheduler> scheduler;
   if (!synchronous_composite_) {
-    begin_frame_source.reset(new DelayBasedBeginFrameSource(
-        base::MakeUnique<DelayBasedTimeSource>(task_runner)));
+    begin_frame_source.reset(new DelayBasedBeginFrameSource(task_runner));
     scheduler.reset(new DisplayScheduler(
         begin_frame_source.get(), task_runner,
         output_surface->capabilities().max_frames_pending));
   }
 
   display_.reset(new Display(
       surface_manager_.get(), shared_bitmap_manager_,
       gpu_memory_buffer_manager_, renderer_settings_,
       surface_id_allocator_->id_namespace(), std::move(begin_frame_source),
       std::move(output_surface), std::move(scheduler),
@@ skipping 76 matching lines @@
   ack.resources = resources;
   client_->ReclaimResources(&ack);
 }
 
 void PixelTestDelegatingOutputSurface::SetBeginFrameSource(
     BeginFrameSource* begin_frame_source) {
   client_->SetBeginFrameSource(begin_frame_source);
 }
 
 }  // namespace cc