ActivityThread: Avoid creating duplicate handlers and reuse mH

sMainThreadHandler is used for notification of changes in
SharedPreferences and refers to a new instance of Handler instead
of the existing instance, mH, of the ActivityThread. Fix to reuse
existing handlers associated with main looper.

Change-Id: I794a5802a9eacdb188bd0619db5e70e3ae89a07d
1 file changed