DNS: Expose stale results through HostResolverImpl.

net/dns/host_resolver_impl.h

Index: net/dns/host_resolver_impl.h
diff --git a/net/dns/host_resolver_impl.h b/net/dns/host_resolver_impl.h
index 24f17a7d6c78c292c981d1646e7ecbf5d01f4e30..895c1e77570445e586d2a575dfc9121b781c1a35 100644
--- a/net/dns/host_resolver_impl.h
+++ b/net/dns/host_resolver_impl.h
@@ -140,6 +140,10 @@ class NET_EXPORT HostResolverImpl
   int ResolveFromCache(const RequestInfo& info,
                        AddressList* addresses,
                        const BoundNetLog& source_net_log) override;
+  int ResolveStaleFromCache(const RequestInfo& info,
+                            AddressList* addresses,
+                            HostCache::EntryStaleness* stale_info,
+                            const BoundNetLog& source_net_log) override;
   void CancelRequest(RequestHandle req) override;
   void SetDnsClientEnabled(bool enabled) override;
   HostCache* GetHostCache() override;
@@ -172,6 +176,7 @@ class NET_EXPORT HostResolverImpl
                     const RequestInfo& info,
                     const IPAddress* ip_address,
                     AddressList* addresses,
+                    HostCache::EntryStaleness* stale_info,
                     const BoundNetLog& request_net_log);
 
   // Tries to resolve |key| as an IP, returns true and sets |net_error| if
@@ -188,7 +193,8 @@ class NET_EXPORT HostResolverImpl
   bool ServeFromCache(const Key& key,
                       const RequestInfo& info,
                       int* net_error,
-                      AddressList* addresses);
+                      AddressList* addresses,
+                      HostCache::EntryStaleness* stale_info);
 
   // If we have a DnsClient with a valid DnsConfig, and |key| is found in the
   // HOSTS file, returns true and fills |addresses|. Otherwise returns false.