QS: Cellular usage warning marker + policy cycle.

Add warning marker to graph from policy, and use the
cycle day from policy to determine the usage period.

Change-Id: I31711eea6a0bf54ad0eb5841d2aa9b8e5927ed58
(cherry picked from commit b5e88019cd69d9320639b6736fabf7f407444967)
diff --git a/packages/SystemUI/res/values/strings.xml b/packages/SystemUI/res/values/strings.xml
index 6a7b450..b79dbbe 100644
--- a/packages/SystemUI/res/values/strings.xml
+++ b/packages/SystemUI/res/values/strings.xml
@@ -572,6 +572,8 @@
     <string name="quick_settings_cellular_detail_data_used"><xliff:g id="data_used" example="2.0 GB">%s</xliff:g> used</string>
     <!-- QuickSettings: Cellular detail panel, data limit format string [CHAR LIMIT=NONE] -->
     <string name="quick_settings_cellular_detail_data_limit"><xliff:g id="data_limit" example="2.0 GB">%s</xliff:g> limit</string>
+    <!-- QuickSettings: Cellular detail panel, data warning format string [CHAR LIMIT=NONE] -->
+    <string name="quick_settings_cellular_detail_data_warning"><xliff:g id="data_limit" example="2.0 GB">%s</xliff:g> warning</string>
 
     <!-- Recents: The empty recents string. [CHAR LIMIT=NONE] -->
     <string name="recents_empty_message">No recent apps</string>