Added UMA metrics for the system update UI in the status area.

ash/metrics/user_metrics_recorder.cc

Index: ash/metrics/user_metrics_recorder.cc
diff --git a/ash/metrics/user_metrics_recorder.cc b/ash/metrics/user_metrics_recorder.cc
index 137199a08e16c2fc12c938a58620d7122d4706ed..065d3dcc74406addaac0d5cf41a40a4ed4b242f3 100644
--- a/ash/metrics/user_metrics_recorder.cc
+++ b/ash/metrics/user_metrics_recorder.cc
@@ -503,6 +503,10 @@ void UserMetricsRecorder::RecordUserMetricsAction(UserMetricsAction action) {
     case UMA_STATUS_AREA_SIGN_OUT:
       base::RecordAction(base::UserMetricsAction("StatusArea_SignOut"));
       break;
+    case UMA_STATUS_AREA_UPDATE_DEFAULT_CLICKED:
+      base::RecordAction(
+          base::UserMetricsAction("StatusArea_Update_Default_Clicked"));

[tdanderson, 2016/07/07 21:36:43]

nit: consider dropping "_Clicked" from the action name to be consistent with
other _CLICKED cases (see line 510 for example)

Also consider dropping "default" from the name since it's not needed for
disambiguation and I don't see that naming convention used elsewhere in this
file.

[bruthig, 2016/07/08 17:49:44]

Acknowledged.

+      break;
     case UMA_STATUS_AREA_VPN_ADD_BUILT_IN_CLICKED:
       base::RecordAction(base::UserMetricsAction("StatusArea_VPN_AddBuiltIn"));
       break;