For consistency with the rest of dart:ui, check required parameters with
assert(param != null) rather than throwing ArgumentError. ArgumentError
is typically reserved for checking the validity of non-null args -- e.g.
that a list has the required number of elements.
* Reland "Added IsolateNameServer functionality (#5410)"
This reverts commit c3976b3c7183f479717bffed3f640fb92afbd3dc.
* Fixed issue with isolate_name_server_test which caused test to timeout
* Disabled thread_annotations on Android as they aren't supported in the
NDK headers for std::mutex. Readded thread annotations to
IsolateNameServer.
* Added IsolateNameServer functionality, which allows for the association
of string names with isolate SendPort ids that can be used to establish
inter-isolate communications.
