Get rid of virtual Display::CreateScheduler.

cc/test/pixel_test_delegating_output_surface.cc

Index: cc/test/pixel_test_delegating_output_surface.cc
diff --git a/cc/test/pixel_test_delegating_output_surface.cc b/cc/test/pixel_test_delegating_output_surface.cc
index c08bd67e1e15c9c9c95080ed30816d7174d9c2a9..f991cc7ece0aa795301dd8a2da8b79b1b0068d88 100644
--- a/cc/test/pixel_test_delegating_output_surface.cc
+++ b/cc/test/pixel_test_delegating_output_surface.cc
@@ -81,23 +81,19 @@ bool PixelTestDelegatingOutputSurface::BindToClient(
   auto* task_runner = base::ThreadTaskRunnerHandle::Get().get();
   CHECK(task_runner);
 
+  if (!synchronous_composite_)
+    begin_frame_source_.reset(new BackToBackBeginFrameSource(task_runner));
+  DCHECK_EQ(synchronous_composite_, !begin_frame_source_);
+
   display_.reset(new Display(surface_manager_.get(), shared_bitmap_manager_,
                              gpu_memory_buffer_manager_, RendererSettings(),
                              surface_id_allocator_->id_namespace(), task_runner,
+                             begin_frame_source_.get(),
                              std::move(output_surface)));
   display_->SetEnlargePassTextureAmountForTesting(enlarge_pass_texture_amount_);
 
-  if (synchronous_composite_) {
-    bool init = display_->InitializeSynchronous(&display_client_);
-    CHECK(init);
-  } else {
-    begin_frame_source_.reset(new BackToBackBeginFrameSource(task_runner));
-    display_->SetBeginFrameSource(begin_frame_source_.get());
-
-    bool init = display_->Initialize(&display_client_);
-    CHECK(init);
-  }
-
+  bool init = display_->Initialize(&display_client_);
+  CHECK(init);
   return true;
 }