Make the virtual keyboard show up on the display with input focus.

ash/mus/keyboard_ui_mus.cc

Index: ash/mus/keyboard_ui_mus.cc
diff --git a/ash/mus/keyboard_ui_mus.cc b/ash/mus/keyboard_ui_mus.cc
index e9d9c20fad8eeb4d1c3f48d516444b25d4a276e2..4cfac1f5b8acfd5bc93ccd71fe3b58a285524ad3 100644
--- a/ash/mus/keyboard_ui_mus.cc
+++ b/ash/mus/keyboard_ui_mus.cc
@@ -35,6 +35,12 @@ void KeyboardUIMus::Show() {
   keyboard_->Show();
 }
 
+void KeyboardUIMus::ShowInDisplay(int64_t display_id) {
+  // TODO(yhanada): Send display id after adding a display_id argument to
+  // |Keyboard::Show()| in keyboard.mojom. See crbug.com/585253.
+  keyboard_->Show();
+}
+
 bool KeyboardUIMus::IsEnabled() {
   return is_enabled_;
 }