Fix more SlidingDrawer flakiness

Wait for isOpened like we did for testAnimateToggle.

Bug 6310562

Change-Id: Ic1a4f5676ec5abf35b0c0a1acda80c98de934a91
diff --git a/tests/tests/widget/src/android/widget/cts/SlidingDrawerTest.java b/tests/tests/widget/src/android/widget/cts/SlidingDrawerTest.java
index 4eec25c..60666ae 100644
--- a/tests/tests/widget/src/android/widget/cts/SlidingDrawerTest.java
+++ b/tests/tests/widget/src/android/widget/cts/SlidingDrawerTest.java
@@ -123,7 +123,7 @@
             }
         });
         assertTrue(drawer.isMoving());
-        assertFalse(drawer.isOpened());
+        assertOpened(false, drawer);
         assertEquals(View.GONE, content.getVisibility());
 
         new PollingCheck() {
@@ -132,7 +132,7 @@
                 return !drawer.isMoving();
             }
         }.run();
-        assertTrue(drawer.isOpened());
+        assertOpened(true, drawer);
         assertEquals(View.VISIBLE, content.getVisibility());
 
         runTestOnUiThread(new Runnable() {
@@ -141,7 +141,7 @@
             }
         });
         assertTrue(drawer.isMoving());
-        assertTrue(drawer.isOpened());
+        assertOpened(true, drawer);
         assertEquals(View.GONE, content.getVisibility());
 
         new PollingCheck() {
@@ -150,7 +150,7 @@
                 return !drawer.isMoving();
             }
         }.run();
-        assertFalse(drawer.isOpened());
+        assertOpened(false, drawer);
         assertEquals(View.GONE, content.getVisibility());
     }