Bug 375280 - [CSS] Add support for CSSEngine to re-apply stylesheets to document roots

Add missed file
diff --git a/tests/org.eclipse.e4.ui.tests.css.core/src/org/eclipse/e4/ui/tests/css/core/CSSEngineTest.java b/tests/org.eclipse.e4.ui.tests.css.core/src/org/eclipse/e4/ui/tests/css/core/CSSEngineTest.java
index dc717a4..8f434c7 100644
--- a/tests/org.eclipse.e4.ui.tests.css.core/src/org/eclipse/e4/ui/tests/css/core/CSSEngineTest.java
+++ b/tests/org.eclipse.e4.ui.tests.css.core/src/org/eclipse/e4/ui/tests/css/core/CSSEngineTest.java
@@ -25,6 +25,9 @@
 		public void setWidgetProvider(Class clazz, IElementProvider provider) {
 			widgetsMap.put(clazz.getName(), provider);
 		}
+
+		public void reapply() {
+		}
 	}
 
 	public abstract static class BaseElement extends ElementAdapter {