Make ConnectionParams an immutable object.

Make ConnectionParams immutable and hashable, which makes it usable as
a key in a Map. Eliminate the few usages of the setters on
ConnectionParams by creating a new object whenever changes are
necessary.

Test: atest CarServiceTest CarServiceUnitTest
Bug: 116226107
Change-Id: I945c79acefe8f53d5073fc94ea5a5e8bf8c06686
1 file changed