TextEditor: get CompletionAssistProvider from editor.

And not from the global object pool. This way, the editors that have
different highlighters for various language dialects, or editors that
support multiple languages in a single editor, can decide themselves on
what CompletionAssistProvider to provide.

Change-Id: Ieebc4a8e7b3de6470fdb8103035aa3b8b2ba6598
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

src/plugins/cmakeprojectmanager/cmakeeditor.h

@@ -34,6 +34,7 @@
 
 #include <texteditor/basetextdocument.h>
 #include <texteditor/basetexteditor.h>
+#include <texteditor/codeassist/completionassistprovider.h>
 #include <utils/uncommentselection.h>
 
 
@@ -58,6 +59,7 @@ public:
     bool duplicateSupported() const { return true; }
     Core::IEditor *duplicate(QWidget *parent);
     Core::Id id() const;
+    TextEditor::CompletionAssistProvider *completionAssistProvider();
 
 private slots:
     void markAsChanged();