Plumbing for TCP FastOpen field trial and enables it for SSL sockets.

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 7b64ffb2d0315f7e8477001473f46739ab0d03b4..8bfe47c7c58965ec4a0e537df0e08b4ab6cee61b 100644
--- a/net/socket/client_socket_pool_manager.cc
+++ b/net/socket/client_socket_pool_manager.cc
@@ -171,15 +171,18 @@ int InitSocketPoolHelper(const GURL& request_url,
                                       &user_agent);
       scoped_refptr<SSLSocketParams> ssl_params;
       if (proxy_info.is_https()) {
-        // TODO (jri): Enable a finch trial to use
-        // COMBINE_CONNECT_AND_WRITE_DESIRED for SSL sockets.
-        proxy_tcp_params =
-            new TransportSocketParams(
-                *proxy_host_port,
-                disable_resolver_cache,
-                ignore_limits,
-                resolution_callback,
-                TransportSocketParams::COMBINE_CONNECT_AND_WRITE_DEFAULT);
+        // Combine connect and write for SSL sockets in TCP FastOpen
+        // field trial.
+        TransportSocketParams::CombineConnectAndWritePolicy
+            combine_connect_and_write =
+                session->params().enable_tcp_fast_open_for_ssl ?
+                    TransportSocketParams::COMBINE_CONNECT_AND_WRITE_DESIRED :
+                    TransportSocketParams::COMBINE_CONNECT_AND_WRITE_DEFAULT;
+        proxy_tcp_params = new TransportSocketParams(*proxy_host_port,
+                                                     disable_resolver_cache,
+                                                     ignore_limits,
+                                                     resolution_callback,
+                                                     combine_connect_and_write);
         // Set ssl_params, and unset proxy_tcp_params
         ssl_params = new SSLSocketParams(proxy_tcp_params,
                                          NULL,
@@ -228,15 +231,17 @@ int InitSocketPoolHelper(const GURL& request_url,
     scoped_refptr<TransportSocketParams> ssl_tcp_params;
     if (proxy_info.is_direct()) {
       // Setup TCP params if non-proxied SSL connection.
-      // TODO (jri): Enable a finch trial to use
-      // COMBINE_CONNECT_AND_WRITE_DESIRED for SSL sockets.
-      ssl_tcp_params =
-          new TransportSocketParams(
-              origin_host_port,
-              disable_resolver_cache,
-              ignore_limits,
-              resolution_callback,
-              TransportSocketParams::COMBINE_CONNECT_AND_WRITE_DEFAULT);
+      // Combine connect and write for SSL sockets in TCP FastOpen field trial.
+      TransportSocketParams::CombineConnectAndWritePolicy
+          combine_connect_and_write =
+              session->params().enable_tcp_fast_open_for_ssl ?
+                  TransportSocketParams::COMBINE_CONNECT_AND_WRITE_DESIRED :
+                  TransportSocketParams::COMBINE_CONNECT_AND_WRITE_DEFAULT;

[mmenke, 2014/09/10 18:29:08]

Optional:  You could move combine_connect_and_write to the top of this function,
and have:

TransportSocketParams::CombineConnectAndWritePolicy combine_connect_and_write =
TransportSocketParams::COMBINE_CONNECT_AND_WRITE_DEFAULT;
if (using_ssl || proxy_info.is_https())
  combine_connect_and_write =
TransportSocketParams::COMBINE_CONNECT_AND_WRITE_DESIRED;

And use it for transport socket params everywhere.  That'd catch the SSL over
non-proxy SSL case, though I suppose connecting to a non-SSL proxy could
theoretically be non-idempotent...Anyways, fine as-is.

[Jana, 2014/09/11 20:04:59]

Since it's not a strong preference for you, I'll leave it as is. The decision is
local to the TransportSocketParams below, and it makes the code easier to read
and reason about, IMO.

+      ssl_tcp_params = new TransportSocketParams(origin_host_port,
+                                                 disable_resolver_cache,
+                                                 ignore_limits,
+                                                 resolution_callback,
+                                                 combine_connect_and_write);
     }
     scoped_refptr<SSLSocketParams> ssl_params =
         new SSLSocketParams(ssl_tcp_params,