Clear cached QUIC network stats when a QUIC handshake fails.

net/http/http_server_properties.h

Index: net/http/http_server_properties.h
diff --git a/net/http/http_server_properties.h b/net/http/http_server_properties.h
index 6ba72dcf71321fc8fbbb2b162b96b578ecd52fbf..f6b71c32a1c8f69e887bfd7ba11ffe03609cd2f0 100644
--- a/net/http/http_server_properties.h
+++ b/net/http/http_server_properties.h
@@ -293,10 +293,14 @@ class NET_EXPORT HttpServerProperties {
   virtual void SetSupportsQuic(bool used_quic,
                                const IPAddress& last_address) = 0;
 
-  // Sets |stats| for |host_port_pair|.
+  // Sets |stats| for |server|.
   virtual void SetServerNetworkStats(const url::SchemeHostPort& server,
                                      ServerNetworkStats stats) = 0;
 
+  // Clears any stats for |server|.
+  virtual void ClearServerNetworkStats(const url::SchemeHostPort& server) = 0;
+
+  // Returns any stats for |server| or nullptr if there are none.
   virtual const ServerNetworkStats* GetServerNetworkStats(
       const url::SchemeHostPort& server) = 0;