mus/ash: Notify the client about AcceleratedWidget in tests.

Send the AcceleratedWidget to the client on init, so that the
compositor can be correctly initialized.

BUG=786453

Change-Id: Iad74feb8d669abf2470702fad890f33c2fe11f91
Reviewed-on: https://chromium-review.googlesource.com/810210
Commit-Queue: Sadrul Chowdhury <[email protected]>
Reviewed-by: Scott Violet <[email protected]>
Cr-Commit-Position: refs/heads/master@{#522027}
diff --git a/ash/test/ash_test_helper.cc b/ash/test/ash_test_helper.cc
index bd2e4da8..28d36c9 100644
--- a/ash/test/ash_test_helper.cc
+++ b/ash/test/ash_test_helper.cc
@@ -45,6 +45,7 @@
 #include "ui/base/material_design/material_design_controller.h"
 #include "ui/base/platform_window_defaults.h"
 #include "ui/base/test/material_design_controller_test_api.h"
+#include "ui/base/ui_base_switches_util.h"
 #include "ui/compositor/scoped_animation_duration_scale_mode.h"
 #include "ui/compositor/test/context_factories_for_test.h"
 #include "ui/display/display.h"
@@ -286,6 +287,8 @@
   window_tree_client_private_ =
       std::make_unique<aura::WindowTreeClientPrivate>(window_tree_client);
   window_tree_client_private_->CallOnConnect();
+  if (!::switches::IsMusHostingViz())
+    window_tree_client_setup_.NotifyClientAboutAcceleratedWidget();
 }
 
 void AshTestHelper::CreateShell() {