[net/dns] Serve requests from HOSTS file if possible.

net/base/host_resolver_impl_unittest.cc

Index: net/base/host_resolver_impl_unittest.cc
diff --git a/net/base/host_resolver_impl_unittest.cc b/net/base/host_resolver_impl_unittest.cc
index b99dbf7b064d8ad818ce8bc13d555039eba9ddff..6e95f2e976b16478d72a26a1c627c40d077cdaf9 100644
--- a/net/base/host_resolver_impl_unittest.cc
+++ b/net/base/host_resolver_impl_unittest.cc
@@ -28,6 +28,7 @@
 #include "net/base/net_util.h"
 #include "net/base/sys_addrinfo.h"
 #include "net/base/test_completion_callback.h"
+#include "net/dns/dns_test_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace net {
@@ -1750,6 +1751,10 @@ TEST_F(HostResolverImplTest, MultipleAttempts) {
   EXPECT_EQ(resolver_proc->resolved_attempt_number(), kAttemptNumberToResolve);
 }
 
+
+// TODO(szym): test HostResolverImpl::DnsTask using MockDnsClient.
+// TODO(szym): test ServeFromHosts using mock DnsHosts.
+
 // TODO(cbentzel): Test a mix of requests with different HostResolverFlags.
 
 }  // namespace net