Core: Register mimetype of softload plugin

Change-Id: I81713d951caaf4e2d97fa1a58c4f512a280af351
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/coreplugin/coreplugin.h

@@ -7,6 +7,7 @@
 #include <qglobal.h>
 
 #include <extensionsystem/iplugin.h>
+#include <extensionsystem/pluginspec.h>
 #include <utils/environment.h>
 
 #include <memory>
@@ -54,6 +55,8 @@ public:
     static void setEnvironmentChanges(const Utils::EnvironmentItems &changes);
     static QString msgCrashpadInformation();
 
+    static void loadMimeFromPlugin(const ExtensionSystem::PluginSpec *plugin);
+
 public slots:
     void fileOpenRequest(const QString &);