SwitchCompat: Fix NPE on makeLayout()

Fixed NPE in makeLayout() when mTextOn or mTextOff is null

Signed-off-by: Taeho Kim <jyte82@gmail.com>

Change-Id: Ic61b6cbe1b46534783b684166d46b5da3b942d3a
Merge "SwitchCompat: Fix NPE on makeLayout()"