Delete code corresponding to old UMA prefs.

chromecast/browser/metrics/cast_metrics_service_client.cc

Index: chromecast/browser/metrics/cast_metrics_service_client.cc
diff --git a/chromecast/browser/metrics/cast_metrics_service_client.cc b/chromecast/browser/metrics/cast_metrics_service_client.cc
index 51f96ccfb06426e5c39c0469c896600c40cc9d8f..6bad1926de446df2211ba8cee8d5964bacc427d7 100644
--- a/chromecast/browser/metrics/cast_metrics_service_client.cc
+++ b/chromecast/browser/metrics/cast_metrics_service_client.cc
@@ -33,7 +33,11 @@ namespace chromecast {
 namespace metrics {
 
 namespace {
+
 const int kStandardUploadIntervalMinutes = 5;
+
+const char kMetricsOldClientID[] = "user_experience_metrics.client_id";
+
 }  // namespace
 
 // static