Fix preconnect crash when we hit max socket limit.

net/socket/client_socket_pool_base.h

Index: net/socket/client_socket_pool_base.h
diff --git a/net/socket/client_socket_pool_base.h b/net/socket/client_socket_pool_base.h
index 2e8c618e1359e2c1b9d764083089168c4a16a7c5..8e6eb139aed050a82d973f0c05319c3e12f24075 100644
--- a/net/socket/client_socket_pool_base.h
+++ b/net/socket/client_socket_pool_base.h
@@ -480,6 +480,11 @@ class ClientSocketPoolBaseHelper
   // I'm not sure if we hit this situation often.
   void CloseOneIdleSocket();
 
+  // Same as CloseOneIdleSocket() except it won't close an idle socket in
+  // |group|.  If |group| is NULL, it is ignored.  Returns true if it closed a
+  // socket.
+  bool CloseOneIdleSocketExceptInGroup(const Group* group);
+
   // Checks if there are stalled socket groups that should be notified
   // for possible wakeup.
   void CheckForStalledSocketGroups();