Make DateTimeView more robust to weird contexts.

In particular, some clients (*ahem* SystemUI) have been
known to inflate RemoteViews with unusual derived contexts
that may not have valid application contexts. DateTimeView
can now resist this.

Bug: 22852700
Change-Id: I5e91ae0e66859f5f5efd7b19c0ae6dfbc26bcc54
1 file changed