Adding a short blacklist period after every previews opt out

components/previews/core/previews_black_list.cc

Index: components/previews/core/previews_black_list.cc
diff --git a/components/previews/core/previews_black_list.cc b/components/previews/core/previews_black_list.cc
index 896507deee1e3391ed33a620df2b9e2777e7eba6..08b9fa2910c4abbb05b4232100bd2bb6038144e1 100644
--- a/components/previews/core/previews_black_list.cc
+++ b/components/previews/core/previews_black_list.cc
@@ -1,21 +1,20 @@
 // 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_black_list.h"
 
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "base/optional.h"
 #include "base/time/clock.h"
-#include "base/time/time.h"
 #include "components/previews/core/previews_black_list_item.h"
 #include "components/previews/core/previews_experiments.h"
 #include "url/gurl.h"
 
 namespace previews {
 
 namespace {
 
 void EvictOldestOptOut(BlackListItemMap* black_list_item_map) {
   // TODO(ryansturm): Add UMA. crbug.com/647717
@@ -55,20 +54,23 @@ PreviewsBlackList::PreviewsBlackList(
   }
 }
 
 PreviewsBlackList::~PreviewsBlackList() {}
 
 void PreviewsBlackList::AddPreviewNavigation(const GURL& url,
                                              bool opt_out,
                                              PreviewsType type) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(url.has_host());
+  if (opt_out) {
+    last_opt_out_time_ = clock_->Now();
+  }
   // If the |black_list_item_map_| has been loaded from |opt_out_store_|,
   // synchronous operations will be accurate. Otherwise, queue the task to run
   // asynchronously.
   if (loaded_) {
     AddPreviewNavigationSync(url, opt_out, type);
   } else {
     QueuePendingTask(base::Bind(&PreviewsBlackList::AddPreviewNavigationSync,
                                 base::Unretained(this), url, opt_out, type));
   }
 }
@@ -90,20 +92,25 @@ void PreviewsBlackList::AddPreviewNavigationSync(const GURL& url,
     return;
   opt_out_store_->AddPreviewNavigation(opt_out, host_name, type, now);
 }
 
 bool PreviewsBlackList::IsLoadedAndAllowed(const GURL& url,
                                            PreviewsType type) const {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(url.has_host());
   if (!loaded_)
     return false;
+  if (last_opt_out_time_ &&
+      clock_->Now() <
+          last_opt_out_time_.value() + params::SingleOptOutDuration()) {
+    return false;
+  }
   PreviewsBlackListItem* black_list_item =
       GetBlackListItem(*black_list_item_map_, url.host());
   return !black_list_item || !black_list_item->IsBlackListed(clock_->Now());
 }
 
 void PreviewsBlackList::ClearBlackList(base::Time begin_time,
                                        base::Time end_time) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK_LE(begin_time, end_time);
   // If the |black_list_item_map_| has been loaded from |opt_out_store_|,