MenuButton: support Mac look & feel

ui/views/controls/button/menu_button.h

Index: ui/views/controls/button/menu_button.h
diff --git a/ui/views/controls/button/menu_button.h b/ui/views/controls/button/menu_button.h
index 696a94146f3f9868e01e2eca55a00dfab53f5e8e..ece355f0559b06a4c6b770777f36209bf0e8c49a 100644
--- a/ui/views/controls/button/menu_button.h
+++ b/ui/views/controls/button/menu_button.h
@@ -53,12 +53,6 @@ class VIEWS_EXPORT MenuButton : public LabelButton {
              bool show_menu_marker);
   ~MenuButton() override;
 
-  bool show_menu_marker() const { return show_menu_marker_; }
-  void set_menu_marker(const gfx::ImageSkia* menu_marker) {
-    menu_marker_ = menu_marker;
-  }
-  const gfx::ImageSkia* menu_marker() const { return menu_marker_; }
-
   const gfx::Point& menu_offset() const { return menu_offset_; }
   void set_menu_offset(int x, int y) { menu_offset_.SetPoint(x, y); }
 
@@ -85,6 +79,7 @@ class VIEWS_EXPORT MenuButton : public LabelButton {
   bool OnKeyPressed(const ui::KeyEvent& event) override;
   bool OnKeyReleased(const ui::KeyEvent& event) override;
   void GetAccessibleState(ui::AXViewState* state) override;
+  void OnEnabledChanged() override;
 
  protected:
   // Paint the menu marker image.
@@ -116,6 +111,10 @@ class VIEWS_EXPORT MenuButton : public LabelButton {
   // use this to make sure a menu is never shown off screen.
   int GetMaximumScreenXCoordinate();
 
+  // Returns the width of the "shoulder" of the menubutton, which is the area

[tapted, 2016/04/27 03:25:11]

nit: menubutton -> MenuButton

[Elly Fong-Jones, 2016/04/28 17:03:12]

Done.

+  // containing the menu marker, and any padding surrounding it.
+  int GetShoulderWidth() const;
+
   // We use a time object in order to keep track of when the menu was closed.
   // The time is used for simulating menu behavior for the menu button; that
   // is, if the menu is shown and the button is pressed, we need to close the
@@ -127,11 +126,11 @@ class VIEWS_EXPORT MenuButton : public LabelButton {
   // Our listener. Not owned.
   MenuButtonListener* listener_;
 
-  // Whether or not we're showing a drop marker.
-  bool show_menu_marker_;
+  // The images to draw for the menu marker, if |show_menu_marker_| is true.

[tapted, 2016/04/27 03:25:11]

I think we can keep the old comment, and variable name (menu_marker_) - they
don't really need to change. Also nudge down to the prior location (below the
bool). Changing it from a raw pointer to a (wrapper around) a ref-counted
pointer I'd keep

[Elly Fong-Jones, 2016/04/28 17:03:12]

Done.

+  gfx::ImageSkia marker_image_;
 
-  // The down arrow used to differentiate the menu button from normal buttons.
-  const gfx::ImageSkia* menu_marker_;
+  // Whether or not we're showing a drop marker.
+  const bool show_menu_marker_;
 
   // If non-null the destructor sets this to true. This is set while the menu is
   // showing and used to detect if the menu was deleted while running.