For other cases calling synchronously is better, because callers might
expect the next get call to return the right browser. However in the
case of installing a browser app, we are holding the mPackages lock
and should not be calling into higher level components synchronously,
so use a new async call for this. This fixes the system-hang until
timeout when installing a new browser app.
Bug: 124452117
Bug: 123775970
Test: manual
Change-Id: Ib820e65c79c2315f41ff0e31268631c973af4511
fafe525798