Extracting NetLog inner classes into their own classes.

net/socket/client_socket_pool_base.cc

Index: net/socket/client_socket_pool_base.cc
diff --git a/net/socket/client_socket_pool_base.cc b/net/socket/client_socket_pool_base.cc
index fd8492f992170e8fa057c73be29ec54e446930f6..389e66c4bf011a8fb74dc424e0ef30a43b9bbe04 100644
--- a/net/socket/client_socket_pool_base.cc
+++ b/net/socket/client_socket_pool_base.cc
@@ -22,6 +22,7 @@
 #include "net/base/net_errors.h"
 #include "net/log/net_log.h"
 #include "net/log/net_log_event_type.h"
+#include "net/log/net_log_source.h"
 
 using base::TimeDelta;
 
@@ -506,7 +507,8 @@ bool ClientSocketPoolBaseHelper::AssignIdleSocketToRequest(
 
 // static
 void ClientSocketPoolBaseHelper::LogBoundConnectJobToRequest(
-    const NetLog::Source& connect_job_source, const Request& request) {
+    const NetLogSource& connect_job_source,
+    const Request& request) {
   request.net_log().AddEvent(NetLogEventType::SOCKET_POOL_BOUND_TO_CONNECT_JOB,
                              connect_job_source.ToEventParametersCallback());
 }