Authentication UI Prompt.

Test: WIP

Bug: 32972298
Change-Id: I379da699141025b1a101e2ad0e5357b3750cb490
diff --git a/res/values/dimens.xml b/res/values/dimens.xml
index a9be865..7e76612 100644
--- a/res/values/dimens.xml
+++ b/res/values/dimens.xml
@@ -56,4 +56,6 @@
 
     <dimen name="drop_icon_height">14dp</dimen>
     <dimen name="drop_icon_width">14dp</dimen>
+
+    <dimen name="header_message_horizontal_padding">8dp</dimen>
 </resources>