Add a new disable_insecure_quic finch parameter to disable insecure 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 8ca344345fce40164f624f9a395ab7634f44cba4..ca55e19c1bd2afb51a614e7f3b3e6101935a832a 100644
--- a/chrome/browser/io_thread.h
+++ b/chrome/browser/io_thread.h
@@ -178,6 +178,7 @@ class IOThread : public content::BrowserThreadDelegate {
     Optional<double> alternative_service_probability_threshold;
 
     Optional<bool> enable_quic;
+    Optional<bool> disable_insecure_quic;
     Optional<bool> enable_quic_for_proxies;
     Optional<bool> enable_quic_port_selection;
     Optional<bool> quic_always_require_handshake_confirmation;
@@ -333,6 +334,11 @@ class IOThread : public content::BrowserThreadDelegate {
       base::StringPiece quic_trial_group,
       bool quic_allowed_by_policy);
 
+  // Returns true if QUIC should be disabled for http:// URLs, as a result
+  // of a field trial.
+  static bool ShouldDisableInsecureQuic(
+      const VariationParameters& quic_trial_params);
+
   // Returns true if the selection of the ephemeral port in bind() should be
   // performed by Chromium, and false if the OS should select the port.  The OS
   // option is used to prevent Windows from posting a security security warning