Protect against negative offsets when calling replace.

Only seems to happen via the monkey.

Fixes bug:5541885 java.lang.ArrayIndexOutOfBoundsException: length=122; index=-5

Change-Id: Iba684c53982f5363990947d2b5b9d7544c952d85
diff --git a/src/com/android/ex/chips/RecipientEditTextView.java b/src/com/android/ex/chips/RecipientEditTextView.java
index 4810087..ed73d71 100644
--- a/src/com/android/ex/chips/RecipientEditTextView.java
+++ b/src/com/android/ex/chips/RecipientEditTextView.java
@@ -1426,7 +1426,7 @@
         Editable editable = getText();
         QwertyKeyListener.markAsReplaced(editable, start, end, "");
         CharSequence chip = createChip(entry, false);
-        if (chip != null) {
+        if (chip != null && start >= 0 && end >= 0) {
             editable.replace(start, end, chip);
         }
         sanitizeBetween();