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 4a7f1ab264af2391f882ff16b68170592b9706c6..9b728f61c103109b4792d0a8d211d7740cf36212 100644
--- a/ash/mus/keyboard_ui_mus.cc
+++ b/ash/mus/keyboard_ui_mus.cc
@@ -37,6 +37,12 @@ void KeyboardUIMus::Show() {
   keyboard_->Show();
 }
 
+void KeyboardUIMus::ShowInDisplay(const 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_;
 }