Remove the ConnCountImpact FieldTrial code.

chrome/renderer/page_load_histograms.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/renderer/page_load_histograms.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
@@ skipping 441 matching lines @@
       case DocumentState::LINK_LOAD_CACHE_STALE_OK:
         PLT_HISTOGRAM(base::FieldTrial::MakeName(
             "PLT.BeginToFinish_LinkLoadStaleOk", "ConnnectBackupJobs"),
             begin_to_finish_all_loads);
         break;
       default:
         break;
     }
   }
 
-  // Histograms to determine if the number of connections has an
-  // impact on PLT.
-  // TODO(jar): Consider removing the per-link-type versions.  We
-  //   really only need LINK_LOAD_NORMAL and NORMAL_LOAD.
-  static const bool use_connection_impact_histogram =
-      base::FieldTrialList::TrialExists("ConnCountImpact");
-  if (use_connection_impact_histogram) {
-    UMA_HISTOGRAM_ENUMERATION(
-        base::FieldTrial::MakeName("PLT.Abandoned", "ConnCountImpact"),
-        abandoned_page ? 1 : 0, 2);
-    switch (load_type) {
-      case DocumentState::NORMAL_LOAD:
-        PLT_HISTOGRAM(base::FieldTrial::MakeName(
-            "PLT.BeginToFinish_NormalLoad", "ConnCountImpact"),
-            begin_to_finish_all_loads);
-        break;
-      case DocumentState::LINK_LOAD_NORMAL:
-        PLT_HISTOGRAM(base::FieldTrial::MakeName(
-            "PLT.BeginToFinish_LinkLoadNormal", "ConnCountImpact"),
-            begin_to_finish_all_loads);
-        break;
-      case DocumentState::LINK_LOAD_RELOAD:
-        PLT_HISTOGRAM(base::FieldTrial::MakeName(
-            "PLT.BeginToFinish_LinkLoadReload", "ConnCountImpact"),
-            begin_to_finish_all_loads);
-        break;
-      case DocumentState::LINK_LOAD_CACHE_STALE_OK:
-        PLT_HISTOGRAM(base::FieldTrial::MakeName(
-            "PLT.BeginToFinish_LinkLoadStaleOk", "ConnCountImpact"),
-            begin_to_finish_all_loads);
-        break;
-      default:
-        break;
-    }
-  }
-
   // Histograms to determine effect of idle socket timeout.
   static const bool use_idle_socket_timeout_histogram =
       base::FieldTrialList::TrialExists("IdleSktToImpact");
   if (use_idle_socket_timeout_histogram) {
     UMA_HISTOGRAM_ENUMERATION(
         base::FieldTrial::MakeName("PLT.Abandoned", "IdleSktToImpact"),
         abandoned_page ? 1 : 0, 2);
     switch (load_type) {
       case DocumentState::NORMAL_LOAD:
         PLT_HISTOGRAM(base::FieldTrial::MakeName(
@@ skipping 484 matching lines @@
 
   DCHECK(document_state);
   DCHECK(ds);
   GURL url(ds->request().url());
   Time start = document_state->start_load_time();
   Time finish = document_state->finish_load_time();
   // TODO(mbelshe): should we log more stats?
   VLOG(1) << "PLT: " << (finish - start).InMilliseconds() << "ms "
           << url.spec();
 }