Add HasKeyInMap

Similar to GetString8ValueFromMap it will be used for validating CDP
messages. Specifically, it will be used to ensure that events have do
not top-level ID attribute. The method does not check types because
clients might treat ID the same way irrespective of the type.

Bug: 513713927
Change-Id: I342961856151195f75ea465e3317cf8324297b3f
3 files changed