Implement _ChildNodeListLazy.removeRange as throwing UnsupportedError

Implement _ChildNodeListLazy.removeRange as throwing UnsupportedError

_ChildNodeListLazy.removeRange used to throw UnsupportedError because ListMixin.removeRange calls setRange.
Make throwing UnsupportedError explicit to avoid relying on the implementation of ListMixin.removeRange
This will unblock the '_closeGap' change.

BUG=
R=lrn@google.com

Committed: https://github.com/dart-lang/sdk/commit/fc7d880c60e8b553e0006141f8b670dba5a1f4bb

[sra1, 2017-06-28 00:38:02]

Description was changed from

==========
Implement _ChildNodeListLazy.removeRange as throwing UnsupportedError

BUG=
==========

to

==========
Implement _ChildNodeListLazy.removeRange as throwing UnsupportedError

BUG=
==========

[sra1, 2017-06-28 00:38:03]

sra@google.com changed reviewers:
+ lrn@google.com

[sra1, 2017-06-28 00:40:47]

Description was changed from

==========
Implement _ChildNodeListLazy.removeRange as throwing UnsupportedError

BUG=
==========

to

==========
Implement _ChildNodeListLazy.removeRange as throwing UnsupportedError

_ChildNodeListLazy.removeRange used to throw UnsupportedError because
ListMixin.removeRange calls setRange.
Make throwing UnsupportedError explicit to avoid relying on the implementation
of ListMixin.removeRange
This will unblock the '_closeGap' change.

BUG=
==========

[Lasse Reichstein Nielsen, 2017-06-28 05:30:52]

lgtm

[sra1, 2017-06-28 16:43:08]

Description was changed from

==========
Implement _ChildNodeListLazy.removeRange as throwing UnsupportedError

_ChildNodeListLazy.removeRange used to throw UnsupportedError because
ListMixin.removeRange calls setRange.
Make throwing UnsupportedError explicit to avoid relying on the implementation
of ListMixin.removeRange
This will unblock the '_closeGap' change.

BUG=
==========

to

==========
Implement _ChildNodeListLazy.removeRange as throwing UnsupportedError

_ChildNodeListLazy.removeRange used to throw UnsupportedError because
ListMixin.removeRange calls setRange.
Make throwing UnsupportedError explicit to avoid relying on the implementation
of ListMixin.removeRange
This will unblock the '_closeGap' change.

BUG=
R=lrn@google.com

Committed:
https://github.com/dart-lang/sdk/commit/fc7d880c60e8b553e0006141f8b670dba5a1f4bb
==========

[sra1, 2017-06-28 16:43:09]

Committed patchset #1 (id:1) manually as
fc7d880c60e8b553e0006141f8b670dba5a1f4bb (presubmit successful).