Support enabling experimental plugins from installer.

Change-Id: Id5f383f58125c44496a3d6936b27638bce48622d
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>
Reviewed-by: Kai Koehne <kai.koehne@digia.com>

src/libs/extensionsystem/pluginmanager.cpp

@@ -907,8 +907,10 @@ void PluginManagerPrivate::writeSettings()
 */
 void PluginManagerPrivate::readSettings()
 {
-    if (globalSettings)
+    if (globalSettings) {
         defaultDisabledPlugins = globalSettings->value(QLatin1String(C_IGNORED_PLUGINS)).toStringList();
+        defaultEnabledPlugins = globalSettings->value(QLatin1String(C_FORCEENABLED_PLUGINS)).toStringList();
+    }
     if (settings) {
         disabledPlugins = settings->value(QLatin1String(C_IGNORED_PLUGINS)).toStringList();
         forceEnabledPlugins = settings->value(QLatin1String(C_FORCEENABLED_PLUGINS)).toStringList();
@@ -1225,9 +1227,14 @@ void PluginManagerPrivate::readPluginPaths()
             collection = new PluginCollection(spec->category());
             pluginCategories.insert(spec->category(), collection);
         }
-        if (defaultDisabledPlugins.contains(spec->name())) {
+        // defaultDisabledPlugins and defaultEnabledPlugins from install settings
+        // is used to override the defaults read from the plugin spec
+        if (!spec->isDisabledByDefault() && defaultDisabledPlugins.contains(spec->name())) {
             spec->setDisabledByDefault(true);
             spec->setEnabled(false);
+        } else if (spec->isDisabledByDefault() && defaultEnabledPlugins.contains(spec->name())) {
+            spec->setDisabledByDefault(false);
+            spec->setEnabled(true);
         }
         if (spec->isDisabledByDefault() && forceEnabledPlugins.contains(spec->name()))
             spec->setEnabled(true);

src/libs/extensionsystem/pluginmanager_p.h

@@ -104,7 +104,8 @@ public:
     QStringList pluginPaths;
     QString extension;
     QList<QObject *> allObjects; // ### make this a QList<QPointer<QObject> > > ?
-    QStringList defaultDisabledPlugins;
+    QStringList defaultDisabledPlugins; // Plugins/Ignored from install settings
+    QStringList defaultEnabledPlugins; // Plugins/ForceEnabled from install settings
     QStringList disabledPlugins;
     QStringList forceEnabledPlugins;
     // delayed initialization