Enable tests in TrayIMETest for MD

ash/common/system/chromeos/ime_menu/ime_list_view.cc

Index: ash/common/system/chromeos/ime_menu/ime_list_view.cc
diff --git a/ash/common/system/chromeos/ime_menu/ime_list_view.cc b/ash/common/system/chromeos/ime_menu/ime_list_view.cc
index c038ebeb401b6c465f3337b44dda06427e24f432..c68d269da7eb47a15d1b7e18501e416130feb63b 100644
--- a/ash/common/system/chromeos/ime_menu/ime_list_view.cc
+++ b/ash/common/system/chromeos/ime_menu/ime_list_view.cc
@@ -180,7 +180,7 @@ class MaterialKeyboardStatusRowView : public views::View {
 
   ~MaterialKeyboardStatusRowView() override {}
 
-  const views::Button* toggle() const { return toggle_; }
+  views::Button* toggle() const { return toggle_; }
   bool is_toggled() const { return toggle_->is_on(); }
 
  protected:
@@ -455,4 +455,13 @@ void ImeListView::FocusCurrentImeIfNeeded() {
   }
 }
 
+ImeListViewTestApi::ImeListViewTestApi(ImeListView* ime_list_view)
+    : ime_list_view_(ime_list_view) {}
+
+ImeListViewTestApi::~ImeListViewTestApi() {}
+
+views::View* ImeListViewTestApi::GetToggleView() const {
+  return ime_list_view_->material_keyboard_status_view_->toggle();
+}
+
 }  // namespace ash