C++: Moved completion/highlighting into the model manager.

This way the editor does not need to know all the details of
instantiating or maintaining classes for highlighting and/or completion,
it can just ask the model manager. The change also enables different
highlighting- or completion-engines without changes to the cppeditor.

Change-Id: I8000d9d9fe446b292defddb2295493cf77d0f14a
Reviewed-by: Leandro Melo <leandro.melo@nokia.com>

src/plugins/cpptools/cppmodelmanager.h

@@ -131,9 +131,11 @@ public:
     virtual QList<CPlusPlus::Document::DiagnosticMessage> extraDiagnostics(
             const QString &fileName, int key = AllExtraDiagnostics) const;
 
-
     void finishedRefreshingSourceFiles(const QStringList &files);
 
+    virtual CppCompletionSupport *completionSupport(Core::IEditor *editor) const;
+    virtual CppHighlightingSupport *highlightingSupport(Core::IEditor *editor) const;
+
 Q_SIGNALS:
     void projectPathChanged(const QString &projectPath);