Don't rely on SSL cipher fallback in proxy auth.

net/http/http_auth_controller.h

Index: net/http/http_auth_controller.h
diff --git a/net/http/http_auth_controller.h b/net/http/http_auth_controller.h
index dbc078e323a95339b14ca56b8ca1e64c5aa9cfa2..4e371c0e7103e15848ceaa45574021ee93482d5b 100644
--- a/net/http/http_auth_controller.h
+++ b/net/http/http_auth_controller.h
@@ -74,6 +74,12 @@ class NET_EXPORT_PRIVATE HttpAuthController
   virtual void DisableAuthScheme(HttpAuth::Scheme scheme);
   virtual void DisableEmbeddedIdentity();
 
+  // Called when the connection has been closed, so the current handler (which
+  // contains state bound to the connection) should be dropped. If retrying on a
+  // new connection, the next call to MaybeGenerateAuthToken will retry the
+  // current auth scheme.
+  virtual void OnConnectionClosed();
+
  private:
   // Actions for InvalidateCurrentHandler()
   enum InvalidateHandlerAction {