Bug 318944 CSSSWTEngineImpl leaks memory
CSSSWTEngineImpl stores too many element contexts. In a memory snapshot, the HashMap size was 15559. This is most probably a leak.
bundles/org.eclipse.e4.ui.css.core/src/org/eclipse/e4/ui/css/core/impl/engine/AbstractCSSEngine.java
}
	
	public void registerCSSValueConverter(ICSSValueConverter converter) {
		if (valueConverters == null)
			valueConverters = new HashMap();
		valueConverters.put(converter.getToType(), converter);
	}
	public void unregisterCSSValueConverter(ICSSValueConverter converter) {
		if (valueConverters == null)
			return;
		valueConverters.remove(converter);
	}
	public ICSSValueConverter getCSSValueConverter(Object toType) {
		if (valueConverters != null) {
			return (ICSSValueConverter) valueConverters.get(toType);
		}
		return null;
	}
	public Object convert(CSSValue value, Object toType, Object context)
			throws Exception {
		Object newValue = null;
		String key = CSSResourcesHelpers.getCSSValueKey(value);
		IResourcesRegistry resourcesRegistry = getResourcesRegistry();
		if (resourcesRegistry != null) {
			if (key != null)
				newValue = resourcesRegistry.getResource(toType, key);
		}
		if (newValue == null) {
			ICSSValueConverter converter = getCSSValueConverter(toType);
			if (converter != null) {