More metrics for proxy connections impact A/B test.

I added socket request times (for new/unused sockets). The hypothesis is that
if proxy servers get overloaded, we will see an increase in request times for
new sockets. Hence, we know that we should tone back a little.

BUG=44501
r=jar

Review URL: http://codereview.chromium.org/3040049

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@55377 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/net/http/http_network_transaction.cc b/net/http/http_network_transaction.cc
index 22f4717..7b2f944 100644
--- a/net/http/http_network_transaction.cc
+++ b/net/http/http_network_transaction.cc
@@ -1340,6 +1340,7 @@
   return OK;
 }
 
+// static
 void HttpNetworkTransaction::LogHttpConnectedMetrics(
     const ClientSocketHandle& handle) {
   UMA_HISTOGRAM_ENUMERATION("Net.HttpSocketType", handle.reuse_type(),