Revert of Moving previews code from components/ to chrome/

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"
@@ skipping 33 matching lines @@
     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(
     base::WeakPtr<PreviewsUIService> previews_ui_service,
-    std::unique_ptr<PreviewsOptOutStore> previews_opt_out_store,
-    const PreviewsIsEnabledCallback& is_enabled_callback) {
+    std::unique_ptr<PreviewsOptOutStore> previews_opt_out_store) {
   DCHECK(ui_task_runner_->BelongsToCurrentThread());
-  is_enabled_callback_ = is_enabled_callback;
   previews_ui_service_ = previews_ui_service;
 
   // Set up the IO thread portion of |this|.
   io_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&PreviewsIOData::InitializeOnIOThread, base::Unretained(this),
                  base::Passed(&previews_opt_out_store)));
 }
 
 void PreviewsIOData::InitializeOnIOThread(
@@ skipping 15 matching lines @@
 }
 
 void PreviewsIOData::ClearBlackList(base::Time begin_time,
                                     base::Time end_time) {
   DCHECK(io_task_runner_->BelongsToCurrentThread());
   previews_black_list_->ClearBlackList(begin_time, end_time);
 }
 
 bool PreviewsIOData::ShouldAllowPreview(const net::URLRequest& request,
                                         PreviewsType type) const {
-  if (is_enabled_callback_.is_null() || !previews_black_list_) {
+  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;
   }
-  if (!is_enabled_callback_.Run(type))
-    return false;
-
-  // The blacklist will disallow certain hosts for periods of time based on
-  // user's opting out of the preview
   PreviewsEligibilityReason status =
       previews_black_list_->IsLoadedAndAllowed(request.url(), type);
   if (status != PreviewsEligibilityReason::ALLOWED) {
     LogPreviewsEligibilityReason(status, type);
     return false;
   }
   net::NetworkQualityEstimator* network_quality_estimator =
       request.context()->network_quality_estimator();
   if (!network_quality_estimator ||
       network_quality_estimator->GetEffectiveConnectionType() <
@@ skipping 15 matching lines @@
           (net::LOAD_VALIDATE_CACHE | net::LOAD_BYPASS_CACHE)) {
     LogPreviewsEligibilityReason(
         PreviewsEligibilityReason::RELOAD_DISALLOWED_FOR_OFFLINE, type);
     return false;
   }
   LogPreviewsEligibilityReason(PreviewsEligibilityReason::ALLOWED, type);
   return true;
 }
 
 }  // namespace previews