Introduce a policy to control the maximal number of connections per proxy server.

net/socket/client_socket_pool_manager.cc

Index: net/socket/client_socket_pool_manager.cc
diff --git a/net/socket/client_socket_pool_manager.cc b/net/socket/client_socket_pool_manager.cc
index f26f876989fb144229a63570eeb59a6e6c038170..1c4bd3f9618f6b4700ebf0a1387657927136445f 100644
--- a/net/socket/client_socket_pool_manager.cc
+++ b/net/socket/client_socket_pool_manager.cc
@@ -27,6 +27,8 @@
 
 namespace net {
 
+const int kDefaultMaxSocketsPerProxyServer = 32;
+
 namespace {
 
 // Total limit of sockets.
@@ -40,7 +42,7 @@ int g_max_sockets_per_group = 6;
 // The max number of sockets to allow per proxy server.  This applies both to
 // http and SOCKS proxies.  See http://crbug.com/12066 and
 // http://crbug.com/44501 for details about proxy server connection limits.
-int g_max_sockets_per_proxy_server = 32;
+int g_max_sockets_per_proxy_server = kDefaultMaxSocketsPerProxyServer;
 
 // Appends information about all |socket_pools| to the end of |list|.
 template <class MapType>