UnifiedEmail: when run monkey will crash by NPE

search feature:
get the NPE in the API setDisableInSearch() of  ConversationListFragment.java
add NPE protect.

Change-Id: Ib993313cd2b76d50f84705a2a210771970f1cf1d
CRs-Fixed: 1096060
diff --git a/src/com/android/mail/ui/ConversationListFragment.java b/src/com/android/mail/ui/ConversationListFragment.java
index e7d8cc8..ac65202 100644
--- a/src/com/android/mail/ui/ConversationListFragment.java
+++ b/src/com/android/mail/ui/ConversationListFragment.java
@@ -1421,10 +1421,11 @@
     }
 
     private void setDisableInSearch() {
-        boolean isLocalSearch = ((ActivityController) mActivity.getAccountController())
-                != null ? ((ActivityController) mActivity
-                        .getAccountController()).getCurrentConversationListContext()
-                        .isLocalSearchExecuted() : false;
+        ActivityController controller = (ActivityController) mActivity.getAccountController();
+        boolean isLocalSearch = false;
+        if (controller != null && controller.getCurrentConversationListContext() != null) {
+            isLocalSearch = controller.getCurrentConversationListContext().isLocalSearchExecuted();
+        }
         if (mFolder != null && mFolder.type == FolderType.SEARCH && isLocalSearch) {
             saveFleetingView();
             mSwipeRefreshWidget.setEnabled(false);