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 +208,22 @@
   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

[Aaron Boodman, 2012/05/29 03:03:08]

I would really prefer this be a separate helper class.

The admin forcelist policy implementation is really a totally different thing
than ExtensionPrefs. Mixing them together ends up requiring these comments to
explain what could be clear from a different factoring.

So add admin_policy.h/cc or whatever and ExtensionPrefs::GetAdminPolicy().

+  virtual std::string GetPolicyProviderName() const OVERRIDE;
+  // Returns true if the extension is allowed by admin policy white- and
+  // blacklists.
+  virtual bool UserMayLoad(const extensions::Extension* extension,
+                           string16* error) const OVERRIDE;
+  // Returns false if the extension is required to remain running, as determined
+  // by Extension::IsRequired(). In practice this enforces the admin policy
+  // forcelist.
+  virtual bool UserMayModifySettings(const extensions::Extension* extension,
+                                     string16* error) const OVERRIDE;
+  // Returns true if the extension is required to remain running, as determined
+  // by Extension::IsRequired(). In practice this enforces the admin policy
+  // forcelist.
+  virtual bool MustRemainEnabled(const extensions::Extension* extension,
+                                 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.
@@ -508,6 +522,12 @@
       const std::string& id,
       bool incognito) const;
 
+  // Internal implementation for certain ManagementPolicy::Delegate methods.
+  // Returns |modifiable_value| if the extension can be modified.
+  bool ManagementPolicyImpl(const extensions::Extension* extension,
+                            string16* error,
+                            bool modifiable_value) const;
+
   // Checks if kPrefBlacklist is set to true in the DictionaryValue.
   // Return false if the value is false or kPrefBlacklist does not exist.
   // This is used to decide if an extension is blacklisted.