Use lock-free lazy initialization for static histogram references

net/socket_stream/socket_stream_metrics_unittest.cc

Index: net/socket_stream/socket_stream_metrics_unittest.cc
===================================================================
--- net/socket_stream/socket_stream_metrics_unittest.cc	(revision 80220)
+++ net/socket_stream/socket_stream_metrics_unittest.cc	(working copy)
@@ -25,7 +25,7 @@
 }
 
 TEST(SocketStreamMetricsTest, ProtocolType) {
-  scoped_refptr<Histogram> histogram;
+  Histogram* histogram;
 
   // First we'll preserve the original values. We need to do this
   // as histograms can get affected by other tests. In particular,
@@ -57,7 +57,7 @@
 }
 
 TEST(SocketStreamMetricsTest, ConnectionType) {
-  scoped_refptr<Histogram> histogram;
+  Histogram* histogram;
 
   // First we'll preserve the original values.
   Histogram::SampleSet original;
@@ -91,7 +91,7 @@
 }
 
 TEST(SocketStreamMetricsTest, OtherNumbers) {
-  scoped_refptr<Histogram> histogram;
+  Histogram* histogram;
 
   // First we'll preserve the original values.
   int64 original_received_bytes = 0;