mash: Reverse the responsibilities of the NewWindowClient.

ash/test/ash_test_helper.cc

Index: ash/test/ash_test_helper.cc
diff --git a/ash/test/ash_test_helper.cc b/ash/test/ash_test_helper.cc
index e92ea0db55093922a9a53aba87ed40150de744e4..5764c4af79f2b452d383e52d9da5268da7df7aa8 100644
--- a/ash/test/ash_test_helper.cc
+++ b/ash/test/ash_test_helper.cc
@@ -7,7 +7,6 @@
 #include "ash/accelerators/accelerator_controller_delegate_aura.h"
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/test/material_design_controller_test_api.h"
-#include "ash/common/test/test_new_window_client.h"
 #include "ash/common/test/test_session_state_delegate.h"
 #include "ash/common/test/test_system_tray_delegate.h"
 #include "ash/common/test/wm_shell_test_api.h"
@@ -156,8 +155,6 @@ void AshTestHelper::SetUp(bool start_session,
   test_screenshot_delegate_ = new TestScreenshotDelegate();
   shell->accelerator_controller_delegate()->SetScreenshotDelegate(
       std::unique_ptr<ScreenshotDelegate>(test_screenshot_delegate_));
-
-  WmShellTestApi().SetNewWindowClient(base::MakeUnique<TestNewWindowClient>());
 }
 
 void AshTestHelper::TearDown() {