Reland 54771 (and 54795) To enable TCP Preconnection by default...

net/socket/client_socket_handle.h

Index: net/socket/client_socket_handle.h
===================================================================
--- net/socket/client_socket_handle.h	(revision 55024)
+++ net/socket/client_socket_handle.h	(working copy)
@@ -132,7 +132,16 @@
   const std::string& group_name() const { return group_name_; }
   int id() const { return pool_id_; }
   ClientSocket* socket() { return socket_.get(); }
-  ClientSocket* release_socket() { return socket_.release(); }
+  ClientSocket* release_socket() {
+    // Update the base class to record things like whether we've ever
+    // transmitted data, and whether the connection was able to be established.
+    // We use this data to construct histograms indicating whether a
+    // speculative connection was ever used, etc., when the ClientSocket is
+    // eventually discarded.
+    if (socket_.get())
+      socket_->UpdateConnectivityState(is_reused());
+    return socket_.release();
+  }
   bool is_reused() const { return is_reused_; }
   base::TimeDelta idle_time() const { return idle_time_; }
   SocketReuseType reuse_type() const {