A runnable is posted for AutoCompleteTextView's PopupDataSetObserver, but there's a possibility that mAdapter would be set to null between when the runnable is run and the time it is posted. This fixes a monkey crash seen in build 29176. Change-Id: Ie7be51db580d6e9775533890e5f6902409bec84d MonkeyCrashID: 2071507494::1632:123:521