Implement header list item.

Bug: 143234489
Test: CarUiListItemTest

Change-Id: I1304ff34535666afd3fcc82653c8e196cb7586f4
diff --git a/car-ui-lib/res/values/dimens.xml b/car-ui-lib/res/values/dimens.xml
index e025301..1ffa471 100644
--- a/car-ui-lib/res/values/dimens.xml
+++ b/car-ui-lib/res/values/dimens.xml
@@ -176,6 +176,8 @@
     <!-- List item  -->
 
     <dimen name="car_ui_list_item_height">116dp</dimen>
+    <dimen name="car_ui_header_list_item_height">116dp</dimen>
+    <dimen name="car_ui_list_item_header_start_inset">0dp</dimen>
     <dimen name="car_ui_list_item_start_inset">0dp</dimen>
     <dimen name="car_ui_list_item_end_inset">0dp</dimen>
     <dimen name="car_ui_list_item_text_start_margin">0dp</dimen>