Made cpp file suffixes take effect after restart.

In CppTools, keep cpp file settings in plugin and settings page
via shared pointer and apply to mime DB in
extensionsInitialized() (after CppEditor has loaded
and registered the mime types).

Task-number: 252299

src/plugins/cpptools/cppfilesettingspage.h

@@ -32,6 +32,7 @@
 
 #include <coreplugin/dialogs/ioptionspage.h>
 #include <QtCore/QPointer>
+#include <QtCore/QSharedPointer>
 #include <QtGui/QWidget>
 
 QT_BEGIN_NAMESPACE
@@ -53,7 +54,7 @@ struct CppFileSettings {
 
     void toSettings(QSettings *) const;
     void fromSettings(QSettings *);
-    void applySuffixesToMimeDB();
+    bool applySuffixesToMimeDB();
 
     bool equals(const CppFileSettings &rhs) const;
 };
@@ -76,8 +77,10 @@ private:
 
 class CppFileSettingsPage : public Core::IOptionsPage
 {
+    Q_DISABLE_COPY(CppFileSettingsPage)
 public:
-    explicit CppFileSettingsPage(QObject *parent = 0);
+    explicit CppFileSettingsPage(QSharedPointer<CppFileSettings> &settings,
+                                 QObject *parent = 0);
     virtual ~CppFileSettingsPage();
 
     virtual QString id() const;
@@ -90,8 +93,8 @@ public:
     virtual void finish() { }
 
 private:
+    const QSharedPointer<CppFileSettings> m_settings;
     QPointer<CppFileSettingsWidget> m_widget;
-    CppFileSettings m_settings;
 };
 
 } // namespace Internal