Update ui/views menus to use async

ui/views/controls/combobox/combobox.h

Index: ui/views/controls/combobox/combobox.h
diff --git a/ui/views/controls/combobox/combobox.h b/ui/views/controls/combobox/combobox.h
index 5cd44549de00c5b340a73098ad130a72dd216625..3de7dc7d880798675fb7c15c307253bc30b74b43 100644
--- a/ui/views/controls/combobox/combobox.h
+++ b/ui/views/controls/combobox/combobox.h
@@ -28,6 +28,7 @@ class ComboboxTestApi;
 
 class ComboboxListener;
 class CustomButton;
+class MenuModelAdapter;
 class MenuRunner;
 class Painter;
 class PrefixSelector;
@@ -113,7 +114,7 @@ class VIEWS_EXPORT Combobox : public PrefixDelegate, public ButtonListener {
  private:
   friend class test::ComboboxTestApi;
 
-  class ComboboxMenuModelAdapter;
+  class ComboboxMenuModel;
 
   // Updates the border according to the current state.
   void UpdateBorder();
@@ -130,6 +131,9 @@ class VIEWS_EXPORT Combobox : public PrefixDelegate, public ButtonListener {
   // Show the drop down list
   void ShowDropDownMenu(ui::MenuSourceType source_type);
 
+  // Cleans up after the menu as closed
+  void OnMenuClosed(Button::ButtonState original_button_state);
+
   // Called when the selection is changed by the user.
   void OnPerformAction();
 
@@ -172,8 +176,8 @@ class VIEWS_EXPORT Combobox : public PrefixDelegate, public ButtonListener {
   // A helper used to select entries by keyboard input.
   std::unique_ptr<PrefixSelector> selector_;
 
-  // Adapts a ComboboxModel for use by a views MenuRunner.
-  std::unique_ptr<ui::MenuModel> menu_model_adapter_;
+  // The ComboboxModel for use by |menu_runner_|.
+  std::unique_ptr<ui::MenuModel> menu_model_;
 
   // Like MenuButton, we use a time object in order to keep track of when the
   // combobox was closed. The time is used for simulating menu behavior; that
@@ -204,7 +208,8 @@ class VIEWS_EXPORT Combobox : public PrefixDelegate, public ButtonListener {
 
   // Set while the dropdown is showing. Ensures the menu is closed if |this| is
   // destroyed.
-  std::unique_ptr<views::MenuRunner> menu_runner_;
+  std::unique_ptr<MenuModelAdapter> menu_model_adapter_;
+  std::unique_ptr<MenuRunner> menu_runner_;
 
   // The image to be drawn for this combobox's arrow.
   gfx::ImageSkia arrow_image_;