Make members of Singleton<T> private and only visible to the singleton type.

net/base/bandwidth_metrics.cc

Index: net/base/bandwidth_metrics.cc
diff --git a/net/base/bandwidth_metrics.cc b/net/base/bandwidth_metrics.cc
index eaaa3c01b89a267881f076d01ddbe4fc67b9afb1..fa23a77da5423e2d61054a0fde7581751aeb06ac 100644
--- a/net/base/bandwidth_metrics.cc
+++ b/net/base/bandwidth_metrics.cc
@@ -2,14 +2,35 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "base/singleton.h"
+#include "base/lazy_instance.h"
 #include "net/base/bandwidth_metrics.h"
 
+static base::LazyInstance<net::BandwidthMetrics> g_bandwidth_metrics(
+    base::LINKER_INITIALIZED);
+
 namespace net {
 
 ScopedBandwidthMetrics::ScopedBandwidthMetrics()
-    : metrics_(Singleton<BandwidthMetrics>::get()),
-      started_(false) {
+    : started_(false) {
+}
+
+ScopedBandwidthMetrics::~ScopedBandwidthMetrics() {
+  if (started_)
+    g_bandwidth_metrics.Get().StopStream();
+}
+
+void ScopedBandwidthMetrics::StartStream() {
+  started_ = true;
+  g_bandwidth_metrics.Get().StartStream();
+}
+
+void ScopedBandwidthMetrics::StopStream() {
+  started_ = false;
+  g_bandwidth_metrics.Get().StopStream();
+}
+
+void ScopedBandwidthMetrics::RecordBytes(int bytes) {
+  g_bandwidth_metrics.Get().RecordBytes(bytes);
 }
 
 }  // namespace net