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

chrome/browser/io_thread.h

Index: chrome/browser/io_thread.h
diff --git a/chrome/browser/io_thread.h b/chrome/browser/io_thread.h
index a989118415d9e012be53f51dbe447e739365f57c..11a41f889be8d468ca738972f6b3a46e5e1d66e6 100644
--- a/chrome/browser/io_thread.h
+++ b/chrome/browser/io_thread.h
@@ -169,6 +169,7 @@ class IOThread : public content::BrowserThreadDelegate {
     bool ignore_certificate_errors;
     uint16 testing_fixed_http_port;
     uint16 testing_fixed_https_port;
+    Optional<bool> enable_tcp_fast_open_for_ssl;
 
     Optional<size_t> initial_max_spdy_concurrent_streams;
     Optional<bool> force_spdy_single_domain;
@@ -265,6 +266,9 @@ class IOThread : public content::BrowserThreadDelegate {
 
   void InitializeNetworkOptions(const base::CommandLine& parsed_command_line);
 
+  // Sets up TCP FastOpen if enabled via field trials or via the command line.
+  void ConfigureTCPFastOpen(const base::CommandLine& command_line);
+
   // Enable SPDY with the given mode, which may contain the following:
   //
   //   "off"                      : Disables SPDY support entirely.