Isolates generic DnsClient from AsyncHostResolver.

net/net.gyp

Index: net/net.gyp
diff --git a/net/net.gyp b/net/net.gyp
index 2694b279b8525e3d3d1f5f1ec528c5231c49bb79..902c165fe85385e3f74f6005600a475cbd088970 100644
--- a/net/net.gyp
+++ b/net/net.gyp
@@ -55,6 +55,8 @@
         'base/backoff_entry.h',
         'base/bandwidth_metrics.cc',
         'base/bandwidth_metrics.h',
+        'base/bigendian.cc',
+        'base/bigendian.h',
         'base/cache_type.h',
         'base/capturing_net_log.cc',
         'base/capturing_net_log.h',
@@ -321,6 +323,8 @@
         'disk_cache/trace.h',
         'dns/async_host_resolver.cc',
         'dns/async_host_resolver.h',
+        'dns/dns_client.cc',
+        'dns/dns_client.h',
         'dns/dns_config_service.cc',
         'dns/dns_config_service.h',
         'dns/dns_config_service_posix.cc',
@@ -333,6 +337,8 @@
         'dns/dns_query.h',
         'dns/dns_response.cc',
         'dns/dns_response.h',
+        'dns/dns_session.cc',
+        'dns/dns_session.h',
         'dns/dns_transaction.cc',
         'dns/dns_transaction.h',
         'dns/serial_worker.cc',
@@ -988,6 +994,7 @@
       'sources': [
         'base/address_list_unittest.cc',
         'base/backoff_entry_unittest.cc',
+        'base/bigendian_unittest.cc',
         'base/cert_database_nss_unittest.cc',
         'base/cert_verifier_unittest.cc',
         'base/cookie_monster_unittest.cc',
@@ -1048,6 +1055,7 @@
         'disk_cache/mapped_file_unittest.cc',
         'disk_cache/storage_block_unittest.cc',
         'dns/async_host_resolver_unittest.cc',
+        'dns/dns_client_unittest.cc',
         'dns/dns_config_service_posix_unittest.cc',
         'dns/dns_config_service_unittest.cc',
         'dns/dns_config_service_win_unittest.cc',