Factor out NetworkID and caching mechanism from n_q_e.{h,cc}

net/net.gypi

Index: net/net.gypi
diff --git a/net/net.gypi b/net/net.gypi
index 9bac24bfe5e33ce32636bcf62879c2a0258ec518..eec1113a0322edb04de8a9440fb401a83dff056b 100644
--- a/net/net.gypi
+++ b/net/net.gypi
@@ -744,12 +744,15 @@
       'nqe/cached_network_quality.cc',
       'nqe/cached_network_quality.h',
       'nqe/external_estimate_provider.h',
+      'nqe/network_id.h',
       'nqe/network_quality.cc',
       'nqe/network_quality.h',
       'nqe/network_quality_estimator.cc',
       'nqe/network_quality_estimator.h',
       'nqe/network_quality_observation.h',
       'nqe/network_quality_observation_source.h',
+      'nqe/network_quality_store.cc',
+      'nqe/network_quality_store.h',
       'nqe/observation_buffer.h',
       'nqe/socket_watcher.cc',
       'nqe/socket_watcher.h',
@@ -1555,6 +1558,7 @@
       'log/write_to_file_net_log_observer_unittest.cc',
       'nqe/network_quality_estimator_unittest.cc',
       'nqe/network_quality_observation_unittest.cc',
+      'nqe/network_quality_store_unittest.cc',
       'nqe/throughput_analyzer_unittest.cc',
       'proxy/dhcp_proxy_script_adapter_fetcher_win_unittest.cc',
       'proxy/dhcp_proxy_script_fetcher_factory_unittest.cc',