Runs most aura tests with both backends

ui/aura/test/aura_test_base.cc

Index: ui/aura/test/aura_test_base.cc
diff --git a/ui/aura/test/aura_test_base.cc b/ui/aura/test/aura_test_base.cc
index 2de0e7712efef7b93dd2db8cb3278fd468898f9b..5a2f907eebc27902ff34813d6c1e74d637ffcaae 100644
--- a/ui/aura/test/aura_test_base.cc
+++ b/ui/aura/test/aura_test_base.cc
@@ -145,6 +145,11 @@ void AuraTestBase::EnableMus() {
   use_mus_ = true;
 }
 
+void AuraTestBase::ConfigureBackend(BackendType type) {
+  if (type == BackendType::MUS)
+    EnableMus();
+}
+
 void AuraTestBase::RunAllPendingInMessageLoop() {
   helper_->RunAllPendingInMessageLoop();
 }
@@ -234,5 +239,18 @@ PropertyConverter* AuraTestBase::GetPropertyConverter() {
   return property_converter_.get();
 }
 
+AuraTestBaseWithType::AuraTestBaseWithType() {}
+
+AuraTestBaseWithType::~AuraTestBaseWithType() {
+  DCHECK(setup_called_);
+}
+
+void AuraTestBaseWithType::SetUp() {
+  DCHECK(!setup_called_);
+  setup_called_ = true;
+  ConfigureBackend(GetParam());
+  AuraTestBase::SetUp();
+}
+
 }  // namespace test
 }  // namespace aura