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 0ecd6487f1dec5b651b7ca1b2e2932b23a2f8230..f2f1f64494483cd208fde923e9e9594f607c819c 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -889,6 +889,9 @@ 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";