Bug 282875 [UI] Allow parts of models to be rendered
We need to change the rendering protocol to allow a 'createGui' to specify the container it should be created under (in SWT-land this would be a Composite). This is necessary to facilitate unit tests and to allow the ad-hoc rendering of chunks of a model within an arbitrary container (i.e. a Dialog or Wizard). In order to do this we'll have to make an API change to the PartFactory's 'createWidget' so that it will get the parent container as a parameter. In order to 'upgrade' an existing PartFactory you would simply replace the code you're currently using to find the correct container with the new parameter's value.
bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/workbench/ui/renderers/swt/TrimPartFactory.java
/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.workbench.ui.renderers.PartFactory#createWidget(org.eclipse
	 * .e4.ui.model.application.MPart)
	 */
	@Override
	public Object createWidget(MPart<?> element) {
		if (!(element instanceof MTrimmedPart<?>))
			return null;
		Composite parentWidget = (Composite) getParentWidget(element);
		Composite trimmedComp = new Composite(parentWidget, SWT.NONE);
		TrimmedPartLayout trimLayout = new TrimmedPartLayout(trimmedComp);
		trimmedComp.setLayout(trimLayout);
		
		return trimLayout.clientArea;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.workbench.ui.renderers.swt.SWTPartFactory#processContents
	 * (org.eclipse.e4.ui.model.application.MPart)
	 */