exo: Run exo in mus+ash

components/exo/test/exo_test_base.cc

 // Copyright 2015 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 "components/exo/test/exo_test_base.h"
 
 #include "base/command_line.h"
+#include "base/memory/ptr_util.h"
 #include "components/exo/test/exo_test_helper.h"
+#include "components/exo/wm_helper_ash.h"
 #include "ui/wm/core/wm_core_switches.h"
 
 namespace exo {
 namespace test {
 
 ////////////////////////////////////////////////////////////////////////////////
 // ExoTestBase, public:
 
 ExoTestBase::ExoTestBase() : exo_test_helper_(new ExoTestHelper) {}
 
 ExoTestBase::~ExoTestBase() {}
 
 void ExoTestBase::SetUp() {
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
   // Disable window animation when running tests.
   command_line->AppendSwitch(wm::switches::kWindowAnimationsDisabled);
   AshTestBase::SetUp();
+  wm_helper_ = base::MakeUnique<WMHelperAsh>();
+  WMHelper::SetInstance(wm_helper_.get());
 }
 
 void ExoTestBase::TearDown() {
+  WMHelper::SetInstance(nullptr);
+  wm_helper_.reset();
   AshTestBase::TearDown();
 }
 
 }  // namespace test
 }  // namespace exo