Delete long-expired GlobalSdch field trial.

chrome/renderer/page_load_histograms.cc

Index: chrome/renderer/page_load_histograms.cc
===================================================================
--- chrome/renderer/page_load_histograms.cc	(revision 202348)
+++ chrome/renderer/page_load_histograms.cc	(working copy)
@@ -411,45 +411,6 @@
                   begin_to_finish_all_loads);
   }
 
-  // Histograms to determine if SDCH has an impact.
-  // TODO(jar): Consider removing per-link load types and the enumeration.
-  static const bool use_sdch_histogram =
-      base::FieldTrialList::TrialExists("GlobalSdch");
-  if (use_sdch_histogram) {
-    UMA_HISTOGRAM_ENUMERATION(
-        base::FieldTrial::MakeName("PLT.LoadType", "GlobalSdch"),
-        load_type, DocumentState::kLoadTypeMax);
-    switch (load_type) {
-      case DocumentState::NORMAL_LOAD:
-        PLT_HISTOGRAM(base::FieldTrial::MakeName(
-            "PLT.BeginToFinish_NormalLoad", "GlobalSdch"),
-            begin_to_finish_all_loads);
-        break;
-      case DocumentState::LINK_LOAD_NORMAL:
-        PLT_HISTOGRAM(base::FieldTrial::MakeName(
-            "PLT.BeginToFinish_LinkLoadNormal", "GlobalSdch"),
-            begin_to_finish_all_loads);
-        break;
-      case DocumentState::LINK_LOAD_RELOAD:
-        PLT_HISTOGRAM(base::FieldTrial::MakeName(
-            "PLT.BeginToFinish_LinkLoadReload", "GlobalSdch"),
-            begin_to_finish_all_loads);
-        break;
-      case DocumentState::LINK_LOAD_CACHE_STALE_OK:
-        PLT_HISTOGRAM(base::FieldTrial::MakeName(
-            "PLT.BeginToFinish_LinkLoadStaleOk", "GlobalSdch"),
-            begin_to_finish_all_loads);
-        break;
-      case DocumentState::LINK_LOAD_CACHE_ONLY:
-        PLT_HISTOGRAM(base::FieldTrial::MakeName(
-            "PLT.BeginToFinish_LinkLoadCacheOnly", "GlobalSdch"),
-            begin_to_finish_all_loads);
-        break;
-      default:
-        break;
-    }
-  }
-
   // TODO(mpcomplete): remove the extension-related histograms after we collect
   // enough data. http://crbug.com/100411
   const bool use_adblock_histogram =