add dimen for voice plate

Bug: 33280056, 64801267

Test: make, flash
Change-Id: I4b97a9fe0db7c86f73d5406a5b2d64b91f3403ca
(cherry picked from commit faa0a4c36c4bf5b8f8fdfff79bd0dd96f2e8c411)
diff --git a/car-stream-ui-lib/res/values/dimens.xml b/car-stream-ui-lib/res/values/dimens.xml
index 9aeb877..5a6fd77 100644
--- a/car-stream-ui-lib/res/values/dimens.xml
+++ b/car-stream-ui-lib/res/values/dimens.xml
@@ -145,4 +145,10 @@
 
     <!-- Height of items in a list. -->
     <dimen name="line_item_height">128dp</dimen>
+
+    <!-- Common icon size for car app -->
+    <dimen name="car_icon_size">44dp</dimen>
+
+    <!-- Touch target size for round or square affordance -->
+    <dimen name="car_touch_target">106dp</dimen>
 </resources>