Since its an arraylist, we need to just replace existing with nulls.

Fixes b/6949402 gmail crashes on launc

Change-Id: I7babea1f55a66940a1a8a3fee53f5a7798f97e9d
diff --git a/src/com/android/mail/browse/ConversationItemView.java b/src/com/android/mail/browse/ConversationItemView.java
index 4e8aedb..eb9fe45 100644
--- a/src/com/android/mail/browse/ConversationItemView.java
+++ b/src/com/android/mail/browse/ConversationItemView.java
@@ -773,6 +773,10 @@
         }
         SpannableString prevSender = null;
         for (SpannableString sender : mHeader.styledSenders) {
+            // There may be null sender strings if there were dupes we had to remove.
+            if (sender == null) {
+                continue;
+            }
             // No more width available, we'll only show fixed fragments.
             if (ellipsize) {
                 break;
diff --git a/src/com/android/mail/browse/SendersView.java b/src/com/android/mail/browse/SendersView.java
index 65e578a..6bcc538 100644
--- a/src/com/android/mail/browse/SendersView.java
+++ b/src/com/android/mail/browse/SendersView.java
@@ -236,7 +236,7 @@
                     // current sender, remove the old entry.
                     if (oldPos != DOES_NOT_EXIST && i > 0 && oldPos == i - 1) {
                         // Remove the old one!
-                        senders.remove(oldPos);
+                        senders.set(oldPos, null);
                     }
                     displayHash.put(currentMessage.sender, i);
                     spannableDisplay.setSpan(style, 0, spannableDisplay.length(), 0);