Implement utility-side host resolver Mojo client.

net/net.gyp

Index: net/net.gyp
diff --git a/net/net.gyp b/net/net.gyp
index 6353acc2ef5b181ea385da598703db0783b04acd..4ff0c178f36371203919c804acd65145dd6c8628 100644
--- a/net/net.gyp
+++ b/net/net.gyp
@@ -717,6 +717,7 @@
             ],
           }, {  # else
             'sources!': [
+              'dns/host_resolver_mojo_unittest.cc',
               'dns/mojo_host_resolver_impl_unittest.cc',
               'proxy/mojo_proxy_resolver_impl_unittest.cc',
             ],
@@ -1254,6 +1255,8 @@
           'target_name': 'net_utility_services',
           'type': 'static_library',
           'sources': [
+            'dns/host_resolver_mojo.cc',
+            'dns/host_resolver_mojo.h',
             'proxy/mojo_proxy_resolver_impl.cc',
             'proxy/mojo_proxy_resolver_impl.h',
           ],