Fix crashing dispatchDraw test

bug:17178924
Change-Id: I19a004827b91925e87071f8a49a033094a45d199
diff --git a/tests/tests/widget/src/android/widget/cts/ExpandableListViewTest.java b/tests/tests/widget/src/android/widget/cts/ExpandableListViewTest.java
index 6a68ed9..67dcb30 100644
--- a/tests/tests/widget/src/android/widget/cts/ExpandableListViewTest.java
+++ b/tests/tests/widget/src/android/widget/cts/ExpandableListViewTest.java
@@ -390,7 +390,7 @@
 
     public void testDispatchDraw() {
         MockExpandableListView expandableListView = new MockExpandableListView(mContext);
-        expandableListView.dispatchDraw(null);
+        expandableListView.dispatchDraw(new Canvas());
     }
 
     private class MockExpandableListAdapter implements ExpandableListAdapter {