Adding back icon size dimen

Bug: 21638256
Change-Id: I522a8e59e63e4a49a087e4fb3aac102595ea6818
diff --git a/res/values/dimens.xml b/res/values/dimens.xml
index 4fa997c..c31a418 100644
--- a/res/values/dimens.xml
+++ b/res/values/dimens.xml
@@ -15,6 +15,8 @@
 -->
 
 <resources>
+    <dimen name="app_icon_size">64dp</dimen>
+
 <!-- Dynamic Grid -->
     <dimen name="dynamic_grid_edge_margin">6dp</dimen>
     <dimen name="dynamic_grid_search_bar_max_width">500dp</dimen>