Add support for implementing getAssists in plugins

Add support for implementing getAssists in plugins

R=scheglov@google.com

Committed: https://github.com/dart-lang/sdk/commit/456f790aa70ff07a5148a5945a5712e5f39a1f8d

[Brian Wilkerson, 2017-06-07 16:05:26]

brianwilkerson@google.com changed reviewers:
+ maxkim@google.com, mfairhurst@google.com, scheglov@google.com

[Brian Wilkerson, 2017-06-07 16:05:27]

Analogous to the fix support, but without the problem of needing to pass in
errors.

[scheglov, 2017-06-07 16:09:19]

lgtm

https://codereview.chromium.org/2924063002/diff/1/pkg/analyzer_plugin/lib/uti...
File pkg/analyzer_plugin/lib/utilities/assist/assist.dart (right):

https://codereview.chromium.org/2924063002/diff/1/pkg/analyzer_plugin/lib/uti...
pkg/analyzer_plugin/lib/utilities/assist/assist.dart:34: void
computeFixes(AssistRequest request, AssistCollector collector);
computeAssists() ?

[Brian Wilkerson, 2017-06-07 16:19:51]

Description was changed from

==========
Add support for implementing getAssists in plugins
==========

to

==========
Add support for implementing getAssists in plugins

R=scheglov@google.com

Committed:
https://github.com/dart-lang/sdk/commit/456f790aa70ff07a5148a5945a5712e5f39a1f8d
==========

[Brian Wilkerson, 2017-06-07 16:19:52]

Committed patchset #1 (id:1) manually as
456f790aa70ff07a5148a5945a5712e5f39a1f8d (presubmit successful).