Wires up InputDeviceClient for mash/mushrome

ash/mus/test/wm_test_helper.h

Index: ash/mus/test/wm_test_helper.h
diff --git a/ash/mus/test/wm_test_helper.h b/ash/mus/test/wm_test_helper.h
index 6b929f27fc0697cfbb69095d643b2548a21ade56..f28c7582fd79f81b9193e27a61e6d3d3bce346ea 100644
--- a/ash/mus/test/wm_test_helper.h
+++ b/ash/mus/test/wm_test_helper.h
@@ -20,6 +20,10 @@ class MessageLoop;
 class SequencedWorkerPoolOwner;
 }
 
+namespace ui {
+class InputDeviceClient;
+}
+
 namespace views {
 class ViewsDelegate;
 }
@@ -79,6 +83,8 @@ class WmTestHelper {
 
   std::unique_ptr<base::SequencedWorkerPoolOwner> blocking_pool_owner_;
 
+  std::unique_ptr<ui::InputDeviceClient> input_device_client_;
+
   DISALLOW_COPY_AND_ASSIGN(WmTestHelper);
 };