Embiggen the progress bar.

BUG=26159818

Change-Id: I12a33be503dd29d03cb85b814b287879c016275d
diff --git a/res/values/dimens.xml b/res/values/dimens.xml
index 060871d..8799785 100644
--- a/res/values/dimens.xml
+++ b/res/values/dimens.xml
@@ -19,6 +19,8 @@
     <dimen name="root_icon_size">24dp</dimen>
     <dimen name="root_icon_margin">0dp</dimen>
 
+    <dimen name="progress_bar_height">4dp</dimen>
+
     <dimen name="grid_width">152dp</dimen>
     <dimen name="grid_height">176dp</dimen>