Remove unused constants from menu_button.h

Change-Id: I076892df0b6e105c8a0af8fb4ef98a8f2464bd75
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1731955Reviewed-by: Robert Liao <robliao@chromium.org>
Commit-Queue: Robert Liao <robliao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683411}

ui/views/controls/button/menu_button.h

@@ -25,10 +25,6 @@ class VIEWS_EXPORT MenuButton : public LabelButton {
  public:
   METADATA_HEADER(MenuButton);
 
-  // How much padding to put on the left and right of the menu marker.
-  static constexpr int kMenuMarkerPaddingLeft = 3;
-  static constexpr int kMenuMarkerPaddingRight = -1;
-
   // Create a Button.
   MenuButton(const base::string16& text,
              MenuButtonListener* menu_button_listener,