Remove content dependencies from content settings providers.

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 d0554547abe9a2f0f48b26b1be783dc4a7432c42..d4ec4e341e501ba63d00d3ab9cea71b99c5906ba 100644
--- a/chrome/browser/content_settings/host_content_settings_map.cc
+++ b/chrome/browser/content_settings/host_content_settings_map.cc
@@ -26,8 +26,6 @@
 #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 "content/public/common/content_switches.h"
 #include "net/base/net_errors.h"
 #include "net/base/static_cookie_policy.h"
 #include "url/gurl.h"
@@ -36,8 +34,6 @@
 #include "extensions/common/constants.h"
 #endif
 
-using content::BrowserThread;
-
 namespace {
 
 typedef std::vector<content_settings::Rule> Rules;
@@ -128,6 +124,7 @@ void HostContentSettingsMap::RegisterProfilePrefs(
 void HostContentSettingsMap::RegisterProvider(
     ProviderType type,
     scoped_ptr<content_settings::ObservableProvider> provider) {
+  DCHECK(CalledOnValidThread());

[vabr (Chromium), 2014/09/23 07:51:00]

Instead of trying to get this functionality from NonThreadSafe, you can include
a thread checker as a data member, and check that, exactly as NonThreadSafe
does.

[Jun Mukai, 2014/09/23 20:48:44]

That is an idea. Please see Bauer's comment.

[Bernhard Bauer, 2014/09/24 08:15:31]

Yeah, that probably makes the most sense. You could put the ThreadChecker into
ObservableProvider, which is the base implementation for all the providers.

[vabr (Chromium), 2014/09/24 09:56:39]

+1 to putting the ThreadChecker (or NonThreadSafe) into ObservableProvider; but
I'm also fine with the current situation

   DCHECK(!content_settings_providers_[type]);
   provider->AddObserver(this);
   content_settings_providers_[type] = provider.release();
@@ -328,7 +325,7 @@ ContentSetting HostContentSettingsMap::GetContentSettingAndMaybeUpdateLastUsage(
     const GURL& secondary_url,
     ContentSettingsType content_type,
     const std::string& resource_identifier) {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DCHECK(CalledOnValidThread());
 
   ContentSetting setting = GetContentSetting(
       primary_url, secondary_url, content_type, resource_identifier);
@@ -573,11 +570,10 @@ void HostContentSettingsMap::OnContentSettingChanged(
 
 HostContentSettingsMap::~HostContentSettingsMap() {
   DCHECK(!prefs_);
-  STLDeleteValues(&content_settings_providers_);
 }
 
 void HostContentSettingsMap::ShutdownOnUIThread() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(CalledOnValidThread());
   DCHECK(prefs_);
   prefs_ = NULL;
   for (ProviderIterator it = content_settings_providers_.begin();
@@ -585,6 +581,8 @@ void HostContentSettingsMap::ShutdownOnUIThread() {
        ++it) {
     it->second->ShutdownOnUIThread();
   }
+  STLDeleteValues(&content_settings_providers_);
+  DetachFromThread();
 }
 
 void HostContentSettingsMap::MigrateObsoleteClearOnExitPref() {