UnmodifiableListView extends class that is not part of Dart API

[sgrekhov]

Please see https://api.dartlang.org/stable/1.16.0/dart-collection/UnmodifiableListView-class.html

Inheritance Object ListBase UnmodifiableListBase UnmodifiableListView

But UnmodifiableListBase is not part of the Dart API. This has several consequences
First, I think, UnmodifiableListBase shold be made internal _UnmodifiableListBase
Second, it shouldn't be shown in documentation. Otherwise documentation became wrong. For example, it shows operator []= as inherited (it is really inherited from UnmodifiableListBase, but documentation shows operator []= as inherited from ListBase (because UnmodifiableListBase is not part of the API and has no documentation)). But operator []= in ListBase sets the value while operator []= in UnmodifiableListView throws UnsupportedError

Documentation issue regarding showing of internal interfaces is dart-lang/dartdoc#1173

[lrhn]

This is similar to issue #26643 in that it exposes an interface from dart:_internal.

We can't make UnmodifiableListBase private because it's from a different library (dart:_internal).
We can either find a way to hide it from the DartDoc, move the class to dart:collection and make it private, or move it and keep it public.
The first option is still open (as an issue against the dartdoc tool), the second one is likely to fail because UnmodifiableListBase is also used in libraries other than dart:collection, so the third option looks better and better.

[floitschG]

This issue was moved to dart-lang/dartdoc#1481