Remove the remnants of the WarmSocketImpact field trial.

net/http/http_network_transaction.cc

Index: net/http/http_network_transaction.cc
diff --git a/net/http/http_network_transaction.cc b/net/http/http_network_transaction.cc
index 467eb940a65d7a6687b7085b3e9257f615036ab5..15cc6f5ebf485a5db01c30715518163f9023120d 100644
--- a/net/http/http_network_transaction.cc
+++ b/net/http/http_network_transaction.cc
@@ -1117,24 +1117,6 @@ void HttpNetworkTransaction::LogTransactionMetrics() const {
                              base::TimeDelta::FromMilliseconds(1),
                              base::TimeDelta::FromMinutes(10), 100);
 
-  static const bool use_warm_socket_impact_histogram =
-      base::FieldTrialList::TrialExists("WarmSocketImpact");
-  if (use_warm_socket_impact_histogram) {
-    UMA_HISTOGRAM_CUSTOM_TIMES(
-        base::FieldTrial::MakeName("Net.Transaction_Latency_b",
-                                   "WarmSocketImpact"),
-        duration,
-        base::TimeDelta::FromMilliseconds(1),
-        base::TimeDelta::FromMinutes(10),
-        100);
-    UMA_HISTOGRAM_CUSTOM_TIMES(
-        base::FieldTrial::MakeName("Net.Transaction_Latency_Total",
-                                   "WarmSocketImpact"),
-        total_duration,
-        base::TimeDelta::FromMilliseconds(1),
-        base::TimeDelta::FromMinutes(10), 100);
-  }
-
   if (!stream_->IsConnectionReused()) {
     UMA_HISTOGRAM_CUSTOM_TIMES(
         "Net.Transaction_Latency_Total_New_Connection",