Make ExtensionContentSettingsStore refcounted.

chrome/browser/content_settings/content_settings_provider.h

Index: chrome/browser/content_settings/content_settings_provider.h
diff --git a/chrome/browser/content_settings/content_settings_provider.h b/chrome/browser/content_settings/content_settings_provider.h
index 1056ea2885b6cf8e7ccc5a62d3808003c9261ac1..23ae1eb447bf26bfeda6459b0f4fca3b4c2d36ff 100644
--- a/chrome/browser/content_settings/content_settings_provider.h
+++ b/chrome/browser/content_settings/content_settings_provider.h
@@ -81,7 +81,8 @@ class ProviderInterface {
   // require a resource identifier to be specified, the |resource_identifier|
   // must be non-empty.
   //
-  // This should only be called on the UI thread.
+  // This should only be called on the UI thread, and not after
+  // ShutdownOnUIThread has been called.

[battre, 2011/07/06 09:12:05]

Just a thought:

should we codify this contract? I.e. do something like

void SetContentSetting(...) {
  DCHECK(not_shut_down);
  SetContentSettingImpl(...);
}
protected:
virtual void SetContentSettingImpl(...) = 0;

[Bernhard Bauer, 2011/07/06 12:06:51]

http://codereview.chromium.org/7218073 adds a DCHECK like that in
content_settings::PrefProvider (which has the only non-empty implementation).

   virtual void SetContentSetting(
       const ContentSettingsPattern& primary_pattern,
       const ContentSettingsPattern& secondary_pattern,
@@ -108,14 +109,22 @@ class ProviderInterface {
   // identifier all content settings for any resource identifieres of the given
   // |content_type| will be reset to CONTENT_SETTING_DEFAULT.
   //
-  // This should only be called on the UI thread.
+  // This should only be called on the UI thread  , and not after

[battre, 2011/07/06 09:12:05]

nit: space

[Bernhard Bauer, 2011/07/06 12:06:51]

Done.

+  // ShutdownOnUIThread has been called.
   virtual void ClearAllContentSettingsRules(
       ContentSettingsType content_type) = 0;
 
   // Resets all content settings to CONTENT_SETTINGS_DEFAULT.
   //
-  // This should only be called on the UI thread.
+  // This should only be called on the UI thread, and not after
+  // ShutdownOnUIThread has been called.
   virtual void ResetToDefaults() = 0;
+
+  // Detaches the Provider from all Profile-related objects like PrefService.
+  // This methods needs to be called before destroying the Profile.
+  // Afterwards, none of the methods above that should only be called on the UI
+  // thread should be called anymore.
+  virtual void ShutdownOnUIThread() {}
 };
 
 }  // namespace content_settings