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/libs/cplusplus/ModelManagerInterface.h

@@ -55,6 +55,8 @@ namespace ProjectExplorer {
 
 namespace CppTools {
     class AbstractEditorSupport;
+    class CppCompletionSupport;
+    class CppHighlightingSupport;
 }
 
 namespace CPlusPlus {
@@ -151,6 +153,9 @@ public:
     virtual QList<CPlusPlus::Document::DiagnosticMessage> extraDiagnostics(
             const QString &fileName, int key = AllExtraDiagnostics) const = 0;
 
+    virtual CppTools::CppCompletionSupport *completionSupport(Core::IEditor *editor) const = 0;
+    virtual CppTools::CppHighlightingSupport *highlightingSupport(Core::IEditor *editor) const = 0;
+
 Q_SIGNALS:
     void documentUpdated(CPlusPlus::Document::Ptr doc);
     void sourceFilesRefreshed(const QStringList &files);