Enable Config::MUS to use classic IME instead of servicified IME.

ui/aura/mus/window_tree_client.cc

Index: ui/aura/mus/window_tree_client.cc
diff --git a/ui/aura/mus/window_tree_client.cc b/ui/aura/mus/window_tree_client.cc
index b69109eb2360aab9f44f2615a3cf70c5837c85c5..128a591547fc3555731dfc7e9b3c030ad9ba63db 100644
--- a/ui/aura/mus/window_tree_client.cc
+++ b/ui/aura/mus/window_tree_client.cc
@@ -52,6 +52,7 @@
 #include "ui/base/ui_base_types.h"
 #include "ui/display/screen.h"
 #include "ui/events/event.h"
+#include "ui/events/event_sink.h"
 #include "ui/gfx/geometry/dip_util.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/gfx/geometry/size.h"
@@ -1282,18 +1283,6 @@ void WindowTreeClient::OnWindowInputEvent(uint32_t event_id,
 
   WindowMus* window = GetWindowByServerId(window_id);  // May be null.
 
-  if (event->IsKeyEvent()) {
-    DCHECK(!matches_pointer_watcher);  // PointerWatcher isn't for key events.
-    if (!window || !window->GetWindow()->GetHost()) {
-      tree_->OnWindowInputEventAck(event_id, ui::mojom::EventResult::UNHANDLED);
-      return;
-    }
-    InputMethodMus* input_method = GetWindowTreeHostMus(window)->input_method();
-    input_method->DispatchKeyEvent(event->AsKeyEvent(),
-                                   CreateEventResultCallback(event_id));
-    return;
-  }
-
   if (matches_pointer_watcher && has_pointer_watcher_) {
     DCHECK(event->IsPointerEvent());
     std::unique_ptr<ui::Event> event_in_dip(ui::Event::Clone(*event));
@@ -1308,6 +1297,15 @@ void WindowTreeClient::OnWindowInputEvent(uint32_t event_id,
     return;
   }
 
+  if (event->IsKeyEvent()) {
+    InputMethodMus* input_method = GetWindowTreeHostMus(window)->input_method();
+    if (input_method) {
+      input_method->DispatchKeyEvent(event->AsKeyEvent(),
+                                     CreateEventResultCallback(event_id));
+      return;
+    }
+  }
+
   EventAckHandler ack_handler(CreateEventResultCallback(event_id));
   // TODO(moshayedi): crbug.com/617222. No need to convert to ui::MouseEvent or
   // ui::TouchEvent once we have proper support for pointer events.