Add content_settings::PolicyProvider and a set of new policies to managed content settings.

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 621c5222888982b7b6a3aa91c62d26498a0be622..eff144361e6eb26acfb03ef9f29a439fd0a6278f 100644
--- a/chrome/browser/content_settings/content_settings_provider.h
+++ b/chrome/browser/content_settings/content_settings_provider.h
@@ -65,6 +65,11 @@ class ProviderInterface {
 
   virtual ~ProviderInterface() {}
 
+  // Returns true whether the content settings provider manages the
+  // |content_type|.
+  virtual bool ContentSettingsTypeIsManaged(
+      ContentSettingsType content_type) = 0;
+
   // Returns a single ContentSetting which applies to a given |requesting_url|,
   // |embedding_url| pair or CONTENT_SETTING_DEFAULT, if no rule applies. For
   // ContentSettingsTypes that require a resource identifier to be specified,