Refactor the various ways to control what users can do to extensions.

chrome/browser/extensions/extension_prefs.h

Index: chrome/browser/extensions/extension_prefs.h
===================================================================
--- chrome/browser/extensions/extension_prefs.h	(revision 138227)
+++ chrome/browser/extensions/extension_prefs.h	(working copy)
@@ -16,6 +16,7 @@
 #include "chrome/browser/extensions/api/content_settings/content_settings_store.h"
 #include "chrome/browser/extensions/extension_prefs_scope.h"
 #include "chrome/browser/extensions/extension_scoped_prefs.h"
+#include "chrome/browser/extensions/management_policy.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/string_ordinal.h"
 
@@ -45,6 +46,7 @@
 //       PrefValueStore::extension_prefs(), which this class populates and
 //       maintains as the underlying extensions change.
 class ExtensionPrefs : public extensions::ContentSettingsStore::Observer,
+                       public extensions::ManagementPolicy::Provider,
                        public ExtensionScopedPrefs {
  public:
   // Key name for a preference that keeps track of per-extension settings. This
@@ -206,10 +208,12 @@
   bool IsAppNotificationDisabled(const std::string& extension_id) const;
   void SetAppNotificationDisabled(const std::string& extension_id, bool value);
 
-  // Is the extension with |extension_id| allowed by policy (checking both
-  // whitelist and blacklist).
-  bool IsExtensionAllowedByPolicy(const std::string& extension_id,
-      extensions::Extension::Location location) const;
+  // ManagementPolicy::Provider
+  virtual std::string PolicyProviderName() const OVERRIDE;
+  // Retruns true if the extension is allowed by admin policy.

[Aaron Boodman, 2012/05/24 08:11:23]

sp: Retruns

+  virtual bool UserMayLoad(const extensions::Extension* extension,

[Pam (message me for reviews), 2012/05/22 12:51:07]

I clarified that this particular management policy provider is checking the
admin policy.

[Aaron Boodman, 2012/05/22 15:56:11]

Ah. You could make that more self-documenting and flexible by factoring this out
into a small helper class which implements ManagementPolicy::Provider.
ExtensionPrefs would have GetAdminPolicyProvider().

[Pam (message me for reviews), 2012/05/23 15:00:58]

How important is this to you? It feels like overcomplication to me.

[Aaron Boodman, 2012/05/24 08:11:23]

Shrug, ok.

+                           extensions::Extension::Location location,
+                           string16* error) const OVERRIDE;
 
   // Checks if extensions are blacklisted by default, by policy. When true, this
   // means that even extensions without an ID should be blacklisted (e.g.