Use ThreadChecker rather than DCHECK_CURRENTLY_ON.

chrome/browser/content_settings/host_content_settings_map.h

 // 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.
 
 // Maps hostnames to custom content settings.  Written on the UI thread and read
 // on any thread.  One instance per profile.
 
 #ifndef CHROME_BROWSER_CONTENT_SETTINGS_HOST_CONTENT_SETTINGS_MAP_H_
 #define CHROME_BROWSER_CONTENT_SETTINGS_HOST_CONTENT_SETTINGS_MAP_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
 #include "base/prefs/pref_change_registrar.h"
 #include "base/threading/platform_thread.h"
+#include "base/threading/thread_checker.h"
 #include "base/tuple.h"
 #include "chrome/browser/content_settings/content_settings_override_provider.h"
 #include "components/content_settings/core/browser/content_settings_observer.h"
 #include "components/content_settings/core/common/content_settings.h"
 #include "components/content_settings/core/common/content_settings_pattern.h"
 #include "components/content_settings/core/common/content_settings_types.h"
 
 class ExtensionService;
 class GURL;
 class PrefService;
@@ skipping 24 matching lines @@
     // TODO(mukai): find the solution.
     INTERNAL_EXTENSION_PROVIDER = 0,
     POLICY_PROVIDER,
     CUSTOM_EXTENSION_PROVIDER,
     OVERRIDE_PROVIDER,
     PREF_PROVIDER,
     DEFAULT_PROVIDER,
     NUM_PROVIDER_TYPES,
   };
 
+  // This should be called on the UI thread, otherwise |thread_checker_| handles
+  // CalledOnValidThread() wrongly.
   HostContentSettingsMap(PrefService* prefs, bool incognito);
 
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
 
   // Adds a new provider for |type|.
   void RegisterProvider(
       ProviderType type,
       scoped_ptr<content_settings::ObservableProvider> provider);
 
   // Returns the default setting for a particular content type. If |provider_id|
@@ skipping 272 matching lines @@
   PrefService* prefs_;
 
   // Whether this settings map is for an OTR session.
   bool is_off_the_record_;
 
   // Content setting providers. This is only modified at construction
   // time and by RegisterExtensionService, both of which should happen
   // before any other uses of it.
   ProviderMap content_settings_providers_;
 
+  base::ThreadChecker thread_checker_;
+
   ObserverList<content_settings::Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(HostContentSettingsMap);
 };
 
 #endif  // CHROME_BROWSER_CONTENT_SETTINGS_HOST_CONTENT_SETTINGS_MAP_H_