Revert "Adding UMA to track previews opt outs and blacklist eligibility"

components/previews/core/previews_io_data.cc

 // Copyright 2016 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 "components/previews/core/previews_io_data.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/files/file_path.h"
 #include "base/location.h"
 #include "base/memory/ptr_util.h"
-#include "base/metrics/histogram.h"
 #include "base/sequenced_task_runner.h"
 #include "base/time/default_clock.h"
 #include "components/previews/core/previews_black_list.h"
 #include "components/previews/core/previews_opt_out_store.h"
 #include "components/previews/core/previews_ui_service.h"
 #include "net/nqe/network_quality_estimator.h"
 #include "net/url_request/url_request.h"
 #include "net/url_request/url_request_context.h"
 #include "url/gurl.h"
 
 namespace previews {
 
-namespace {
-
-void LogPreviewsEligibilityReason(PreviewsEligibilityReason status,
-                                  PreviewsType type) {
-  switch (type) {
-    case PreviewsType::OFFLINE:
-      UMA_HISTOGRAM_ENUMERATION(
-          "Previews.EligibilityReason.Offline", static_cast<int>(status),
-          static_cast<int>(PreviewsEligibilityReason::LAST));
-      break;
-    default:
-      NOTREACHED();
-  }
-}
-
-}  // namespace
-
 PreviewsIOData::PreviewsIOData(
     const scoped_refptr<base::SingleThreadTaskRunner>& ui_task_runner,
     const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner)
     : ui_task_runner_(ui_task_runner),
       io_task_runner_(io_task_runner),
       weak_factory_(this) {}
 
 PreviewsIOData::~PreviewsIOData() {}
 
 void PreviewsIOData::Initialize(
@@ skipping 32 matching lines @@
   DCHECK(io_task_runner_->BelongsToCurrentThread());
   previews_black_list_->ClearBlackList(begin_time, end_time);
 }
 
 bool PreviewsIOData::ShouldAllowPreview(const net::URLRequest& request,
                                         PreviewsType type) const {
   if (!IsPreviewsTypeEnabled(type))
     return false;
   // The blacklist will disallow certain hosts for periods of time based on
   // user's opting out of the preview
-  if (!previews_black_list_) {
-    LogPreviewsEligibilityReason(
-        PreviewsEligibilityReason::BLACKLIST_UNAVAILABLE, type);
-    return false;
-  }
-  PreviewsEligibilityReason status =
-      previews_black_list_->IsLoadedAndAllowed(request.url(), type);
-  if (status != PreviewsEligibilityReason::ALLOWED) {
-    LogPreviewsEligibilityReason(status, type);
+  if (!previews_black_list_ ||
+      !previews_black_list_->IsLoadedAndAllowed(request.url(), type)) {
     return false;
   }
   net::NetworkQualityEstimator* network_quality_estimator =
       request.context()->network_quality_estimator();
-  if (!network_quality_estimator ||
-      network_quality_estimator->GetEffectiveConnectionType() <
-          net::EFFECTIVE_CONNECTION_TYPE_OFFLINE) {
-    LogPreviewsEligibilityReason(
-        PreviewsEligibilityReason::NETWORK_QUALITY_UNAVAILABLE, type);
+  if (!network_quality_estimator)
     return false;
-  }
-  if (network_quality_estimator->GetEffectiveConnectionType() >
-      net::EFFECTIVE_CONNECTION_TYPE_SLOW_2G) {
-    LogPreviewsEligibilityReason(PreviewsEligibilityReason::NETWORK_NOT_SLOW,
-                                 type);
-    return false;
-  }
-  LogPreviewsEligibilityReason(PreviewsEligibilityReason::ALLOWED, type);
-  return true;
+
+  net::EffectiveConnectionType effective_connection_type =
+      network_quality_estimator->GetEffectiveConnectionType();
+  return effective_connection_type >= net::EFFECTIVE_CONNECTION_TYPE_OFFLINE &&
+         effective_connection_type <= net::EFFECTIVE_CONNECTION_TYPE_SLOW_2G;
 }
 
 }  // namespace previews