Add two more charger states to Platform.CrOSEvent.

This adds SpringPowerSupply.Original.Low and SpringPowerSupply.ChargerIdle.

BUG=chrome-os-partner:23973
TEST=manual

Change-Id: I35478741e128891667bfd64c45b379c7c9b7d602
Reviewed-on: https://chromium-review.googlesource.com/176707
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
Commit-Queue: Luigi Semenzato <semenzato@chromium.org>
Tested-by: Luigi Semenzato <semenzato@chromium.org>
diff --git a/metrics/metrics_library.cc b/metrics/metrics_library.cc
index ba8e900..3165561 100644
--- a/metrics/metrics_library.cc
+++ b/metrics/metrics_library.cc
@@ -43,6 +43,8 @@
   "Attestation.OriginSpecificExhausted",  // 6
   "SpringPowerSupply.Original.High",  // 7
   "SpringPowerSupply.Other.High",  // 8
+  "SpringPowerSupply.Original.Low",  // 9
+  "SpringPowerSupply.ChargerIdle",  // 10
 };
 
 time_t MetricsLibrary::cached_enabled_time_ = 0;