Remove obsolete plugin storage

Plugin storage was used before the value cache existed. With the
value cache this is no longer used and can be removed.

refs #660

src/blackmisc/pluginstorageprovider.h

@@ -1,63 +0,0 @@
-/* Copyright (C) 2015
- * swift project Community / Contributors
- *
- * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
- * directory of this distribution and at http://www.swift-project.org/license.html. No part of swift project,
- * including this file, may be copied, modified, propagated, or distributed except according to the terms
- * contained in the LICENSE file.
- */
-
-//! \file
-
-#ifndef BLACKMISC_PLUGINSTORAGEPROVIDER_H
-#define BLACKMISC_PLUGINSTORAGEPROVIDER_H
-
-#include "blackmisc/variant.h"
-#include <QObject>
-
-namespace BlackMisc
-{
-    //! Interface for a plugin storage provider.
-    //! It allows plugins to store any arbitrary data which can be packed into a \sa CVariant
-    //! Every plugin shall have its own data area. This means multiple plugins can store
-    //! data under the same key without overwriting each other.
-    class IPluginStorageProvider
-    {
-    public:
-        //! Destructor
-        virtual ~IPluginStorageProvider() {}
-
-        //! Get plugin data stored for object and identified by key
-        virtual CVariant getPluginData(const QObject *obj, const QString &key) const = 0;
-
-        //! Store plugin data for object, identified by key and packed into value
-        virtual void setPluginData(const QObject *obj, const QString &key, const CVariant &value) = 0;
-    };
-
-    //! Delegating class which can be directly used to access an \sa IPluginStorageProvider instance
-    class CPluginStorageAware
-    {
-    protected:
-        //! \copydoc IPluginStorageProvider::getPluginData
-        virtual CVariant getPluginData(const QObject *obj, const QString &key) const
-        {
-            return m_pluginStorageProvider->getPluginData(obj, key);
-        }
-
-        //! \copydoc IPluginStorageProvider::setPluginData
-        virtual void setPluginData(const QObject *obj, const QString &key, const CVariant &value)
-        {
-            m_pluginStorageProvider->setPluginData(obj, key, value);
-        }
-
-        //! Constructor
-        CPluginStorageAware(IPluginStorageProvider *pluginStorageProvider) :
-            m_pluginStorageProvider(pluginStorageProvider)
-        {
-            Q_ASSERT(pluginStorageProvider);
-        }
-        IPluginStorageProvider *m_pluginStorageProvider = nullptr; //!< access to object
-    };
-} // namespace
-
-#endif