mus: Makes ~WindowTreeClient reset context factory

ash/mus/window_manager_unittest.cc

Index: ash/mus/window_manager_unittest.cc
diff --git a/ash/mus/window_manager_unittest.cc b/ash/mus/window_manager_unittest.cc
index 45fc419fc4d31dfcf5e6e3d3d8c68ddab9e8c94d..4c2c0cd0e88246778ebfd775b94812bdbd1a1108 100644
--- a/ash/mus/window_manager_unittest.cc
+++ b/ash/mus/window_manager_unittest.cc
@@ -66,29 +66,7 @@ class WindowManagerTest : public service_manager::test::ServiceTest {
   WindowManagerTest() : service_manager::test::ServiceTest("mash_unittests") {}
   ~WindowManagerTest() override {}
 
-  // service_manager::test::ServiceTest:
-  void SetUp() override {
-    service_manager::test::ServiceTest::SetUp();
-
-    // This test connects to the real mus. This results in
-    // aura::WindowTreeClient resetting the context_factory on Env. As all
-    // tests share the same Env (see mash_test_suite) we need to restore the
-    // context_factory when done.
-    aura::Env* env = aura::Env::GetInstance();
-    initial_context_factory_ = env->context_factory();
-    initial_context_factory_private_ = env->context_factory_private();
-  }
-
-  void TearDown() override {
-    aura::Env* env = aura::Env::GetInstance();
-    env->set_context_factory(initial_context_factory_);
-    env->set_context_factory_private(initial_context_factory_private_);
-  }
-
  private:
-  ui::ContextFactory* initial_context_factory_ = nullptr;
-  ui::ContextFactoryPrivate* initial_context_factory_private_ = nullptr;
-
   DISALLOW_COPY_AND_ASSIGN(WindowManagerTest);
 };