Bug 214492 [Markers] Need to be able to add filters to existing markers views
Currently you can only add filters to a new markerContentProvider. We need to able to bind them to existing markerContentProviders as well.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/MarkerContentGenerator.java
MarkerField[] getAllFields() {
		return allFields;
	}
	/**
	 * Get the category name from the receiver.
	 */
	String getCategoryName() {
		return configurationElement
				.getAttribute(ATTRIBUTE_DEFAULT_MARKER_GROUPING);
	}
	/**
	 * Return the configuration elements for the receiver.
	 * 
	 * @return IConfigurationElement[]
	 */
	IConfigurationElement[] getFilterReferences() {
		return configurationElement
				.getChildren(ELEMENT_MARKER_FIELD_FILTER_GROUP);
	}
	/**
	 * Return the id of the receiver.
	 * 
	 * @return String
	 */
	public String getId() {
		return configurationElement
				.getAttribute(MarkerSupportConstants.ATTRIBUTE_ID);
	}
	/**
	 * Get the list of initially visible fields