Add a whitelist for QUIC hosts.

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index f2afc2729b3588b1cfd072645e77eba91315adba..4b3b1748e368b376b492df9fa47789c4382619dd 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -884,6 +884,9 @@ const char kProxyServer[]                   = "proxy-server";
 // the server.
 const char kQuicConnectionOptions[]         = "quic-connection-options";
 
+// Specifies a comma separated list of hosts to whitelist QUIC for.
+const char kQuicHostWhitelist[]             = "quic-host-whitelist";
+
 // Specifies the maximum length for a QUIC packet.
 const char kQuicMaxPacketLength[]           = "quic-max-packet-length";