Properly Clear Chip Container.

Author: kevzlou7979

gwt-material/src/main/java/gwt/material/design/client/ui/MaterialChipContainer.java

@@ -50,14 +50,6 @@ protected void onLoad() {
         chipHandler.load();
     }
 
-    @Override
-    protected void onUnload() {
-        super.onUnload();
-
-        chipList.clear();
-        selected.clear();
-    }
-
     protected void add(Widget child, Element container) {
         super.add(child, container);
 
@@ -99,8 +91,10 @@ public boolean remove(Widget w) {
     }
 
     public void clear() {
-        for (MaterialChip chip : chipList) {
-            remove(chip);
+        for (Widget chip : getChildren()) {
+            if (chip instanceof MaterialChip) {
+                remove(chip);
+            }
         }
     }