Remove remaining use of the deprecated MessageLoopProxy

chromecast/base/metrics/cast_metrics_helper.h

Index: chromecast/base/metrics/cast_metrics_helper.h
diff --git a/chromecast/base/metrics/cast_metrics_helper.h b/chromecast/base/metrics/cast_metrics_helper.h
index dd4f5f013df701f5be068886df1e204b0559b0c9..0650c0e533713dc9d2df429a9e00f4b78cdcbac8 100644
--- a/chromecast/base/metrics/cast_metrics_helper.h
+++ b/chromecast/base/metrics/cast_metrics_helper.h
@@ -112,8 +112,8 @@ class CastMetricsHelper {
   virtual void SetRecordActionCallback(const RecordActionCallback& callback);
 
  protected:
-  // Creates a CastMetricsHelper instance with no MessageLoopProxy. This should
-  // only be used by tests, since invoking any non-overridden methods on this
+  // Creates a CastMetricsHelper instance with no task runner. This should only
+  // be used by tests, since invoking any non-overridden methods on this
   // instance will cause a failure.
   CastMetricsHelper();