Add probe to warm data reduction proxy

components/data_reduction_proxy/common/data_reduction_proxy_switches.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/data_reduction_proxy/common/data_reduction_proxy_switches.h"
 
 namespace data_reduction_proxy {
 namespace switches {
 
 // The origin of the data reduction proxy.
@@ skipping 12 matching lines @@
 // The origin of the data reduction proxy fallback.
 const char kDataReductionProxyFallback[] = "spdy-proxy-auth-fallback";
 
 // A test key for data reduction proxy authentication.
 const char kDataReductionProxyKey[] = "spdy-proxy-auth-value";
 
 // Sets a canary URL to test before committing to using the data reduction
 // proxy. Note this canary does not go through the data reduction proxy.
 const char kDataReductionProxyProbeURL[] = "data-reduction-proxy-probe-url";
 
+// Sets a URL to fetch to warm up the data reduction proxy on startup and
+// network changes.
+const char kDataReductionProxyWarmupURL[] = "data-reduction-proxy-warmup-url";
+
 // The origin of the data reduction SSL proxy.
 const char kDataReductionSSLProxy[] = "data-reduction-ssl-proxy";
 
 // Disables the origin of the data reduction proxy dev.
 const char kDisableDataReductionProxyDev[] =
     "disable-spdy-proxy-dev-auth-origin";
 
 // Enables the origin of the data reduction proxy dev.
 const char kEnableDataReductionProxyDev[] =
     "enable-spdy-proxy-dev-auth-origin";
 
 // Enable the data reduction proxy.
 const char kEnableDataReductionProxy[] = "enable-spdy-proxy-auth";
 
 // Enable the alternative data reduction proxy.
 const char kEnableDataReductionProxyAlt[] = "enable-data-reduction-proxy-alt";
 
 }  // namespace switches
 }  // namespace data_reduction_proxy