views/mus: Change 'reset(new' to base::MakeUnqiue.

ui/views/mus/window_tree_host_mus.cc

Index: ui/views/mus/window_tree_host_mus.cc
diff --git a/ui/views/mus/window_tree_host_mus.cc b/ui/views/mus/window_tree_host_mus.cc
index 745c1a6c2fdd65a36f17f882c75689f4ded97520..caed894310e48e65017d0b3d2b56882ca5b1a22f 100644
--- a/ui/views/mus/window_tree_host_mus.cc
+++ b/ui/views/mus/window_tree_host_mus.cc
@@ -54,7 +54,7 @@ WindowTreeHostMus::WindowTreeHostMus(NativeWidgetMus* native_widget,
   dispatcher()->set_transform_events(false);
   compositor()->SetHostHasTransparentBackground(true);
 
-  input_method_.reset(new InputMethodMus(this, window));
+  input_method_ = base::MakeUnique<InputMethodMus>(this, window);
   SetSharedInputMethod(input_method_.get());
 }