Split SocketWatcher and SocketWatcherFactory out of NQE

net/nqe/network_quality_estimator.h

Index: net/nqe/network_quality_estimator.h
diff --git a/net/nqe/network_quality_estimator.h b/net/nqe/network_quality_estimator.h
index 2abc9fd7d6f7bffbcea10f7262ff497dbeb225c8..f38deb8d1ae5444d8c92f3a3d161d92d8a039871 100644
--- a/net/nqe/network_quality_estimator.h
+++ b/net/nqe/network_quality_estimator.h
@@ -31,7 +31,6 @@
 #include "net/socket/socket_performance_watcher_factory.h"
 
 namespace base {
-class SingleThreadTaskRunner;
 class TickClock;
 }  // namespace base
 
@@ -326,9 +325,6 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest,
                            TestExternalEstimateProviderMergeEstimates);
 
-  class SocketWatcher;
-  class SocketWatcherFactory;
-
   // Value of round trip time observations is in base::TimeDelta.
   typedef nqe::internal::Observation<base::TimeDelta> RttObservation;
   typedef nqe::internal::ObservationBuffer<base::TimeDelta>