Added UMA metrics for display settings UI in the status area.

base/metrics/user_metrics.h

Index: base/metrics/user_metrics.h
diff --git a/base/metrics/user_metrics.h b/base/metrics/user_metrics.h
index c80bac038d78dc4782f732532d11ab068efad268..93701e8fd209897a144af07dcab0f197cc8c6ff9 100644
--- a/base/metrics/user_metrics.h
+++ b/base/metrics/user_metrics.h
@@ -26,9 +26,9 @@ namespace base {
 //   not good: "SSLDialogShown", "PageLoaded", "DiskFull"
 // We use this to gather anonymized information about how users are
 // interacting with the browser.
-// WARNING: In calls to this function, UserMetricsAction and a
-// string literal parameter must be on the same line, e.g.
-//   RecordAction(UserMetricsAction("my extremely long action name"));
+// WARNING: In calls to this function, UserMetricsAction should be followed by a
+// string literal parameter and not a variable e.g.
+//   RecordAction(UserMetricsAction("my action name"));
 // This ensures that our processing scripts can associate this action's hash
 // with its metric name. Therefore, it will be possible to retrieve the metric
 // name from the hash later on.