Add tests for TLS fallback on connection reset and close.

net/test/spawned_test_server/base_test_server.h

Index: net/test/spawned_test_server/base_test_server.h
diff --git a/net/test/spawned_test_server/base_test_server.h b/net/test/spawned_test_server/base_test_server.h
index 5c47ebc05a397568ed535ef63aeaaa82b32ac82a..a5e3287786208e98f398a1840501be418fef6928 100644
--- a/net/test/spawned_test_server/base_test_server.h
+++ b/net/test/spawned_test_server/base_test_server.h
@@ -111,6 +111,14 @@ class BaseTestServer {
       TLS_INTOLERANT_TLS1_2 = 3,  // Intolerant of TLS 1.2 or higher.
     };
 
+    // Values which control how the server reacts in response to a ClientHello
+    // it is intolerant of.
+    enum TLSIntoleranceType {
+      TLS_INTOLERANCE_ALERT = 0,  // Send a handshake_failure alert.
+      TLS_INTOLERANCE_CLOSE = 1,  // Close the connection.
+      TLS_INTOLERANCE_RESET = 2,  // Send a TCP reset.
+    };
+
     // Initialize a new SSLOptions using CERT_OK as the certificate.
     SSLOptions();
 
@@ -171,6 +179,10 @@ class BaseTestServer {
     // negotiates an intolerant TLS version in order to test version fallback.
     TLSIntolerantLevel tls_intolerant;
 
+    // If |tls_intolerant| is not TLS_INTOLERANT_NONE, how the server reacts to
+    // an intolerant TLS version.
+    TLSIntoleranceType tls_intolerance_type;
+
     // fallback_scsv_enabled, if true, causes the server to process the
     // TLS_FALLBACK_SCSV cipher suite. This cipher suite is sent by Chrome
     // when performing TLS version fallback in response to an SSL handshake