Use ThreadChecker rather than DCHECK_CURRENTLY_ON.

chrome/browser/content_settings/host_content_settings_map.cc

Index: chrome/browser/content_settings/host_content_settings_map.cc
diff --git a/chrome/browser/content_settings/host_content_settings_map.cc b/chrome/browser/content_settings/host_content_settings_map.cc
index d0bb869ca3b5f0206fe6bfe32704536541b70497..c835e8d0990cbf96c75375c250c660aa28915178 100644
--- a/chrome/browser/content_settings/host_content_settings_map.cc
+++ b/chrome/browser/content_settings/host_content_settings_map.cc
@@ -17,7 +17,6 @@
 #include "chrome/browser/content_settings/content_settings_policy_provider.h"
 #include "chrome/browser/content_settings/content_settings_pref_provider.h"
 #include "chrome/browser/content_settings/content_settings_utils.h"
-#include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/url_constants.h"
 #include "components/content_settings/core/browser/content_settings_details.h"
@@ -26,7 +25,6 @@
 #include "components/content_settings/core/browser/content_settings_rule.h"
 #include "components/content_settings/core/common/content_settings_pattern.h"
 #include "components/pref_registry/pref_registry_syncable.h"
-#include "content/public/browser/browser_thread.h"
 #include "net/base/net_errors.h"
 #include "net/base/static_cookie_policy.h"
 #include "url/gurl.h"
@@ -35,8 +33,6 @@
 #include "extensions/common/constants.h"
 #endif
 
-using content::BrowserThread;
-
 namespace {
 
 typedef std::vector<content_settings::Rule> Rules;
@@ -81,6 +77,8 @@ HostContentSettingsMap::HostContentSettingsMap(PrefService* prefs,
 #endif
       prefs_(prefs),
       is_off_the_record_(incognito) {
+  // This should be called on the UI thread, otherwise |thread_checker_| handles

[Bernhard Bauer, 2014/10/15 12:37:02]

Why is this comment here? It might make more sense in the header.

[Jun Mukai, 2014/10/15 23:46:18]

I misunderstood your previous comment. Moved back to the header.

+  // CalledOnValidThread() wrongly.
   content_settings::ObservableProvider* policy_provider =
       new content_settings::PolicyProvider(prefs_);
   policy_provider->AddObserver(this);
@@ -327,7 +325,7 @@ ContentSetting HostContentSettingsMap::GetContentSettingAndMaybeUpdateLastUsage(
     const GURL& secondary_url,
     ContentSettingsType content_type,
     const std::string& resource_identifier) {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DCHECK(thread_checker_.CalledOnValidThread());
 
   ContentSetting setting = GetContentSetting(
       primary_url, secondary_url, content_type, resource_identifier);
@@ -576,7 +574,7 @@ HostContentSettingsMap::~HostContentSettingsMap() {
 }
 
 void HostContentSettingsMap::ShutdownOnUIThread() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(prefs_);
   prefs_ = NULL;
   for (ProviderIterator it = content_settings_providers_.begin();