Converts mash_wm_apptests to unit tests

mash/wm/accelerator_registrar_unittest.cc

Index: mash/wm/accelerator_registrar_unittest.cc
diff --git a/mash/wm/accelerator_registrar_apptest.cc b/mash/wm/accelerator_registrar_unittest.cc
similarity index 95%
rename from mash/wm/accelerator_registrar_apptest.cc
rename to mash/wm/accelerator_registrar_unittest.cc
index a16d21059d5c6dc4c59ca280ddde452059775a08..fa755bc1d42df770c37ef6563a9a2dd0ffbf7ccf 100644
--- a/mash/wm/accelerator_registrar_apptest.cc
+++ b/mash/wm/accelerator_registrar_unittest.cc
@@ -11,7 +11,7 @@
 #include "components/mus/public/cpp/window.h"
 #include "components/mus/public/interfaces/accelerator_registrar.mojom.h"
 #include "mojo/public/cpp/bindings/binding.h"
-#include "mojo/shell/public/cpp/application_test_base.h"
+#include "mojo/shell/public/cpp/shell_test.h"
 
 using mus::mojom::AcceleratorHandler;
 using mus::mojom::AcceleratorHandlerPtr;
@@ -65,9 +65,9 @@ class TestAcceleratorHandler : public AcceleratorHandler {
   DISALLOW_COPY_AND_ASSIGN(TestAcceleratorHandler);
 };
 
-class AcceleratorRegistrarTest : public mojo::test::ApplicationTestBase {
+class AcceleratorRegistrarTest : public mojo::test::ShellTest {
  public:
-  AcceleratorRegistrarTest() {}
+  AcceleratorRegistrarTest() : mojo::test::ShellTest("exe:mash_unittests") {}
   ~AcceleratorRegistrarTest() override {}
 
  protected: