Null check for recent labels list.

Change-Id: I36c076f0f4969812c1dcbde322aa7b0b277e14ef
diff --git a/src/com/android/mail/AccountSpinnerAdapter.java b/src/com/android/mail/AccountSpinnerAdapter.java
index a296dbe..686aeb2 100644
--- a/src/com/android/mail/AccountSpinnerAdapter.java
+++ b/src/com/android/mail/AccountSpinnerAdapter.java
@@ -137,6 +137,9 @@
      */
     public void setCurrentFolder(Folder folder) {
         mCurrentFolder = folder;
+        if (mRecentFolders == null) {
+            mRecentFolders = new RecentFolderList(mCurrentAccount);
+        }
         mRecentFolderList = mRecentFolders.changeCurrentFolder(folder);
     }
 
@@ -146,7 +149,9 @@
      */
     public void setCurrentAccount(Account account) {
         mCurrentAccount = account;
-        mRecentFolders = new RecentFolderList(mCurrentAccount);
+        if (mRecentFolders == null) {
+            mRecentFolders = new RecentFolderList(mCurrentAccount);
+        }
         mRecentFolderList = mRecentFolders.getSortedArray(mCurrentFolder);
         notifyDataSetChanged();
     }