Removes code using mus client lib

ui/views/test/views_test_helper_aura.cc

Index: ui/views/test/views_test_helper_aura.cc
diff --git a/ui/views/test/views_test_helper_aura.cc b/ui/views/test/views_test_helper_aura.cc
index f9fe6f1b125fc9759753a0183ecc4d51087a8a54..50196b58508987d1c3092fe8680b3e607479eadb 100644
--- a/ui/views/test/views_test_helper_aura.cc
+++ b/ui/views/test/views_test_helper_aura.cc
@@ -79,7 +79,7 @@ void ViewsTestHelperAura::TearDown() {
 }
 
 gfx::NativeWindow ViewsTestHelperAura::GetContext() {
-  if (PlatformTestHelper::IsAuraMusClient()) {
+  if (PlatformTestHelper::IsMus()) {
     // GetContext() returns the root of a WindowTreeHost associated with a
     // single display that is intended for an ash like environment. Such a
     // configuration doesn't make sense for aura-mus-client, where it's testing