DO NOT MERGE. Check for null chip text.

Fixes bug:5324605 java.lang.NullPointerException at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:420)

Change-Id: If84a447d1209c5802298f5e886b4580fd3112248
diff --git a/src/com/android/ex/chips/RecipientEditTextView.java b/src/com/android/ex/chips/RecipientEditTextView.java
index 692ce30..6e14e89 100644
--- a/src/com/android/ex/chips/RecipientEditTextView.java
+++ b/src/com/android/ex/chips/RecipientEditTextView.java
@@ -903,7 +903,9 @@
                 if (entry != null) {
                     QwertyKeyListener.markAsReplaced(editable, start, end, "");
                     CharSequence chipText = createChip(entry, false);
-                    editable.replace(start, end, chipText);
+                    if (chipText != null) {
+                        editable.replace(start, end, chipText);
+                    }
                 }
                 dismissDropDown();
                 return true;