TextEditor: Further *Editor/*EditorWidget disentangling

In most cases, the *Editor constructor does not need to
access the *EditorWidget.

Change-Id: I1f5c076a0f723d5d82b398e8c250c7bd1d47eb17
Reviewed-by: Christian Stenger <christian.stenger@digia.com>

src/plugins/cmakeprojectmanager/cmakeeditor.h

@@ -50,12 +50,13 @@ class CMakeEditor : public TextEditor::BaseTextEditor
     Q_OBJECT
 
 public:
-    CMakeEditor(CMakeEditorWidget *);
+    CMakeEditor();
 
     Core::IEditor *duplicate();
-
     QString contextHelpId() const;
 
+    friend class CMakeEditorWidget;
+
 private slots:
     void markAsChanged();
     void build();