Early connection migration in QUIC.

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 bf5b93d5b3361510f4a75b36eafc69517e7c6748..85e5f507e8ca1e3a8bc7f2b7e2387abb0e66efea 100644
--- a/chrome/browser/io_thread.h
+++ b/chrome/browser/io_thread.h
@@ -244,6 +244,7 @@ class IOThread : public content::BrowserThreadDelegate {
     Optional<bool> quic_disable_preconnect_if_0rtt;
     std::unordered_set<std::string> quic_host_whitelist;
     Optional<bool> quic_migrate_sessions_on_network_change;
+    Optional<bool> quic_migrate_sessions_early;
     bool enable_user_alternate_protocol_ports;
     // NetErrorTabHelper uses |dns_probe_service| to send DNS probes when a
     // main frame load fails with a DNS error in order to provide more useful
@@ -488,6 +489,10 @@ class IOThread : public content::BrowserThreadDelegate {
   static bool ShouldQuicMigrateSessionsOnNetworkChange(
       const VariationParameters& quic_trial_params);
 
+  // Returns true if QUIC should migrate sessions early.
+  static bool ShouldQuicMigrateSessionsEarly(
+      const VariationParameters& quic_trial_params);
+
   // Returns the maximum length for QUIC packets, based on any flags in
   // |command_line| or the field trial.  Returns 0 if there is an error
   // parsing any of the options, or if the default value should be used.