Extensions: Make it possible for permission parsing code to return a detailed error message.

chrome/common/extensions/permissions/settings_override_permission.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_COMMON_EXTENSIONS_PERMISSIONS_SETTINGS_OVERRIDE_PERMISSION_H_
 #define CHROME_COMMON_EXTENSIONS_PERMISSIONS_SETTINGS_OVERRIDE_PERMISSION_H_
 
 #include <string>
 
 #include "extensions/common/permissions/api_permission.h"
 
 namespace extensions {
 
 // Takes care of creating custom permission messages for extensions that
 // override settings.
 class SettingsOverrideAPIPermission : public APIPermission {
  public:
   SettingsOverrideAPIPermission(
       const APIPermissionInfo* permission, const std::string& setting_value);
   virtual ~SettingsOverrideAPIPermission();
 
   // APIPermission overrides.
   virtual bool HasMessages() const OVERRIDE;
   virtual PermissionMessages GetMessages() const OVERRIDE;
   virtual bool Check(const APIPermission::CheckParam* param) const OVERRIDE;
   virtual bool Contains(const APIPermission* rhs) const OVERRIDE;
   virtual bool Equal(const APIPermission* rhs) const OVERRIDE;
-  virtual bool FromValue(const base::Value* value) OVERRIDE;
+  virtual bool FromValue(const base::Value* value, std::string* error) OVERRIDE;
   virtual scoped_ptr<base::Value> ToValue() const OVERRIDE;
   virtual APIPermission* Clone() const OVERRIDE;
   virtual APIPermission* Diff(const APIPermission* rhs) const OVERRIDE;
   virtual APIPermission* Union(const APIPermission* rhs) const OVERRIDE;
   virtual APIPermission* Intersect(const APIPermission* rhs) const OVERRIDE;
   virtual void Write(IPC::Message* m) const OVERRIDE;
   virtual bool Read(const IPC::Message* m, PickleIterator* iter) OVERRIDE;
   virtual void Log(std::string* log) const OVERRIDE;
 
  private:
   std::string setting_value_;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_COMMON_EXTENSIONS_PERMISSIONS_SETTINGS_OVERRIDE_PERMISSION_H_