Force HostContentSettingsMap to be destroyed on its owning thread.

components/content_settings/core/browser/host_content_settings_map.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 "components/content_settings/core/browser/host_content_settings_map.h"
 
 #include <stddef.h>
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "base/time/clock.h"
 #include "build/build_config.h"
 #include "components/content_settings/core/browser/content_settings_default_provider.h"
 #include "components/content_settings/core/browser/content_settings_details.h"
 #include "components/content_settings/core/browser/content_settings_info.h"
 #include "components/content_settings/core/browser/content_settings_observable_provider.h"
 #include "components/content_settings/core/browser/content_settings_policy_provider.h"
 #include "components/content_settings/core/browser/content_settings_pref_provider.h"
 #include "components/content_settings/core/browser/content_settings_provider.h"
 #include "components/content_settings/core/browser/content_settings_registry.h"
@@ skipping 144 matching lines @@
   content_settings::PatternPair patterns = GetPatternsFromScopingType(
       website_settings_info->scoping_type(), primary_url, secondary_url);
   return patterns;
 }
 
 }  // namespace
 
 HostContentSettingsMap::HostContentSettingsMap(PrefService* prefs,
                                                bool is_incognito_profile,
                                                bool is_guest_profile)
-    :
+    : RefcountedKeyedService(base::ThreadTaskRunnerHandle::Get()),
 #ifndef NDEBUG
       used_from_thread_id_(base::PlatformThread::CurrentId()),
 #endif
       prefs_(prefs),
       is_incognito_(is_incognito_profile || is_guest_profile),
       weak_ptr_factory_(this) {
   DCHECK(!(is_incognito_profile && is_guest_profile));
 
   content_settings::PolicyProvider* policy_provider =
       new content_settings::PolicyProvider(prefs_);
@@ skipping 628 matching lines @@
     const ContentSettingsPattern& secondary_pattern,
     ContentSettingsType content_type,
     std::string resource_identifier) {
   for (content_settings::Observer& observer : observers_) {
     observer.OnContentSettingChanged(primary_pattern, secondary_pattern,
                                      content_type, resource_identifier);
   }
 }
 
 HostContentSettingsMap::~HostContentSettingsMap() {
+  DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(!prefs_);
 }
 
 void HostContentSettingsMap::ShutdownOnUIThread() {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(prefs_);
   prefs_ = NULL;
   for (const auto& provider_pair : content_settings_providers_)
     provider_pair.second->ShutdownOnUIThread();
 }
@@ skipping 181 matching lines @@
         if (primary_pattern)
           *primary_pattern = rule.primary_pattern;
         if (secondary_pattern)
           *secondary_pattern = rule.secondary_pattern;
         return base::WrapUnique(rule.value.get()->DeepCopy());
       }
     }
   }
   return std::unique_ptr<base::Value>();
 }