Add activatable MenuItems

Activatable MenuItems will toggle their view's setActivated() state
every time they are clicked. In reference-design chassis, this means
they will turn black-on-white with a white circle background when activated.
OEMs can customize what the icons look like when activated, but individual
apps cannot.

Fixes: 142410396
Test: Manually
Change-Id: Ife3251b461e3d3a945d492490c613e9b490f87a5
diff --git a/car-ui-lib/res/values/dimens.xml b/car-ui-lib/res/values/dimens.xml
index 371df82..ddb0067 100644
--- a/car-ui-lib/res/values/dimens.xml
+++ b/car-ui-lib/res/values/dimens.xml
@@ -57,7 +57,9 @@
     <dimen name="car_ui_toolbar_icon_size">@dimen/car_ui_primary_icon_size</dimen>
     <dimen name="car_ui_toolbar_title_margin_start">@dimen/car_ui_padding_2</dimen>
     <dimen name="car_ui_toolbar_menu_item_margin">@dimen/car_ui_padding_2</dimen>
-    <dimen name="car_ui_toolbar_icon_ripple_radius">48dp</dimen>
+    <dimen name="car_ui_toolbar_menu_item_icon_ripple_radius">48dp</dimen>
+    <dimen name="car_ui_toolbar_menu_item_icon_size">@dimen/car_ui_primary_icon_size</dimen>
+    <dimen name="car_ui_toolbar_menu_item_icon_background_size">54dp</dimen>
 
     <!-- Internal artifacts. Do not overlay -->
     <item name="wrap_content" format="integer" type="dimen">-2</item>