Make ripple on dark backgrounds more visible

Provide greater UX feedback when speed dial tile is tapped

Bug: 18373617
Change-Id: I75c0900ed87b7427917dda2c40d9677d75f38d3b
diff --git a/res-common/values/colors.xml b/res-common/values/colors.xml
index e12634a..376fd3f 100644
--- a/res-common/values/colors.xml
+++ b/res-common/values/colors.xml
@@ -20,8 +20,8 @@
 
     <color name="focus_color">#44ff0000</color>
 
-    <!-- Color of ripples used by Theme.Material. Taken from res/values/colors_material.xml -->
-    <color name="ripple_material_dark">#20ffffff</color>
+    <!-- Color of ripples used for views with dark backgrounds -->
+    <color name="ripple_material_dark">#a0ffffff</color>
 
     <!-- Divider color for header separator -->
     <color name="primary_text_color">#363636</color>