PullToRefresh feature for syncing contacts (Flag Control)

This feature only supports Google accounts. It will sync all Google
accounts in all contacts view, and will sync Google account itself in
Google contacts view.

BUG 28625097

Change-Id: Icdfff5e201d827d3f6866ad1d8835ef3fdbd43b0
diff --git a/res/values/colors.xml b/res/values/colors.xml
index 8089a2e..3656089 100644
--- a/res/values/colors.xml
+++ b/res/values/colors.xml
@@ -84,4 +84,9 @@
     <!-- Color of background of all empty states. -->
     <color name="empty_state_background">#efefef</color>
 
+    <!-- Colors of swipeRefreshLayout's spinning circle. -->
+    <color name="swipe_refresh_color1">#0f9d58</color>
+    <color name="swipe_refresh_color2">#dd4b37</color>
+    <color name="swipe_refresh_color3">#4285f4</color>
+    <color name="swipe_refresh_color4">#f4b400</color>
 </resources>