HostResolver supports optional CNAME lookups.

chrome/browser/intranet_redirect_detector.cc

Index: chrome/browser/intranet_redirect_detector.cc
diff --git a/chrome/browser/intranet_redirect_detector.cc b/chrome/browser/intranet_redirect_detector.cc
index 3a527f65d95c4fd19e1c778ec5b2ad8d9844896a..8466cd7673b2e24f56c666c04a9f62082bd06517 100644
--- a/chrome/browser/intranet_redirect_detector.cc
+++ b/chrome/browser/intranet_redirect_detector.cc
@@ -158,6 +158,7 @@ IntranetRedirectHostResolverProc::IntranetRedirectHostResolverProc(
 
 int IntranetRedirectHostResolverProc::Resolve(const std::string& host,
                                               net::AddressFamily address_family,
+                                              net::HostResolverFlags flags,
                                               net::AddressList* addrlist) {
   // We'd love to just ask the IntranetRedirectDetector, but we may not be on
   // the same thread.  So just use the heuristic that any all-lowercase a-z
@@ -167,5 +168,5 @@ int IntranetRedirectHostResolverProc::Resolve(const std::string& host,
       (host.find_first_not_of("abcdefghijklmnopqrstuvwxyz") ==
           std::string::npos)) ?
       net::ERR_NAME_NOT_RESOLVED :
-      ResolveUsingPrevious(host, address_family, addrlist);
+      ResolveUsingPrevious(host, address_family, flags, addrlist);
 }