GUIInvoke takes a QObject* to avoid callbacks after object lifetime

* The GUIInvoke object takes a QObject, and uses QPointer to check that
  it hasn't been deleted when the callback fires. This prevents delayed
  callbacks from executing after the object has been deleted and
  crashing.
* In most cases the pointer is just 'this'.

qrenderdoc/Code/pyrenderdoc/PythonContext.cpp

@@ -805,7 +805,7 @@ void PythonContext::outstream_del(PyObject *self)
     PythonContext *context = redirector->context;
 
     // delete the context on the UI thread.
-    GUIInvoke::call([context]() { delete context; });
+    GUIInvoke::call(context, [context]() { delete context; });
   }
 }