Bump DEPS to linter `0.1.31`.

Bump DEPS to linter `0.1.31`.

Linter `0.1.31`:

* New `prefer_foreach` lint.
* New `use_string_buffers` rule.
* New `unnecessary_overrides` rule.
* New `join_return_with_assignment_when_possible` rule.
* New `use_to_and_as_if_applicable` rule.
* New `avoid_setters_without_getters` rule.
* New `always_put_control_body_on_new_line` rule.
* New `avoid_positional_boolean_parameters` rule.
* New `always_require_non_null_named_parameters` rule.
* New `prefer_conditional_assignment` rule.
* New `prefer_conditional_assignment` rule.
* New `avoid_types_on_closure_parameters` rule.
* New `always_put_control_body_on_new_line` rule.
* New `use_setters_to_change_properties` rule.
* New `avoid_returning_this` rule.
* New `avoid_annotating_with_dynamic_when_not_required` rule.
* New `prefer_constructors_over_static_methods` rule.
* New `avoid_returning_null` rule.
* New `avoid_classes_with_only_static_members` rule.
* New `avoid_null_checks_in_equality_operators` rule.
* New `avoid_catches_without_on_clauses` rule.
* New `avoid_catching_errors` rule.
* New `use_rethrow_when_possible` rule.
* Many lint fixes (notably `prefer_final_fields`, `unnecessary_lambdas`, `await_only_futures`, `cascade_invocations`, `avoid_types_on_closure_parameters`, and `overridden_fields`).
* Significant performance improvements for `prefer_interpolation_to_compose_strings`.
* New `unnecessary_this` rule.
* New `prefer_initiliazling_formals` rule.

BUG=
R=brianwilkerson@google.com

Committed: https://github.com/dart-lang/sdk/commit/8fba8ccd978a5f8230fb18da0efee0ea53da943e

[pquitslund, 2017-05-08 19:48:28]

pquitslund@google.com changed reviewers:
+ brianwilkerson@google.com, devoncarew@google.com

[Brian Wilkerson, 2017-05-08 19:52:55]

lgtm

[pquitslund, 2017-05-08 19:53:56]

Description was changed from

==========
Bump DEPS to linter `0.1.31`.

Linter `0.1.31`:

* New `prefer_foreach` lint.
* New `use_string_buffers` rule.
* New `unnecessary_overrides` rule.
* New `join_return_with_assignment_when_possible` rule.
* New `use_to_and_as_if_applicable` rule.
* New `avoid_setters_without_getters` rule.
* New `always_put_control_body_on_new_line` rule.
* New `avoid_positional_boolean_parameters` rule.
* New `always_require_non_null_named_parameters` rule.
* New `prefer_conditional_assignment` rule.
* New `prefer_conditional_assignment` rule.
* New `avoid_types_on_closure_parameters` rule.
* New `always_put_control_body_on_new_line` rule.
* New `use_setters_to_change_properties` rule.
* New `avoid_returning_this` rule.
* New `avoid_annotating_with_dynamic_when_not_required` rule.
* New `prefer_constructors_over_static_methods` rule.
* New `avoid_returning_null` rule.
* New `avoid_classes_with_only_static_members` rule.
* New `avoid_null_checks_in_equality_operators` rule.
* New `avoid_catches_without_on_clauses` rule.
* New `avoid_catching_errors` rule.
* New `use_rethrow_when_possible` rule.
* Many lint fixes (notably `prefer_final_fields`, `unnecessary_lambdas`,
`await_only_futures`, `cascade_invocations`,
`avoid_types_on_closure_parameters`, and `overridden_fields`).
* Significant performance improvements for
`prefer_interpolation_to_compose_strings`.
* New `unnecessary_this` rule.
* New `prefer_initiliazling_formals` rule.

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

to

==========
Bump DEPS to linter `0.1.31`.

Linter `0.1.31`:

* New `prefer_foreach` lint.
* New `use_string_buffers` rule.
* New `unnecessary_overrides` rule.
* New `join_return_with_assignment_when_possible` rule.
* New `use_to_and_as_if_applicable` rule.
* New `avoid_setters_without_getters` rule.
* New `always_put_control_body_on_new_line` rule.
* New `avoid_positional_boolean_parameters` rule.
* New `always_require_non_null_named_parameters` rule.
* New `prefer_conditional_assignment` rule.
* New `prefer_conditional_assignment` rule.
* New `avoid_types_on_closure_parameters` rule.
* New `always_put_control_body_on_new_line` rule.
* New `use_setters_to_change_properties` rule.
* New `avoid_returning_this` rule.
* New `avoid_annotating_with_dynamic_when_not_required` rule.
* New `prefer_constructors_over_static_methods` rule.
* New `avoid_returning_null` rule.
* New `avoid_classes_with_only_static_members` rule.
* New `avoid_null_checks_in_equality_operators` rule.
* New `avoid_catches_without_on_clauses` rule.
* New `avoid_catching_errors` rule.
* New `use_rethrow_when_possible` rule.
* Many lint fixes (notably `prefer_final_fields`, `unnecessary_lambdas`,
`await_only_futures`, `cascade_invocations`,
`avoid_types_on_closure_parameters`, and `overridden_fields`).
* Significant performance improvements for
`prefer_interpolation_to_compose_strings`.
* New `unnecessary_this` rule.
* New `prefer_initiliazling_formals` rule.

BUG=
R=brianwilkerson@google.com

Committed:
https://github.com/dart-lang/sdk/commit/8fba8ccd978a5f8230fb18da0efee0ea53da943e
==========

[pquitslund, 2017-05-08 19:53:58]

Committed patchset #1 (id:1) manually as
8fba8ccd978a5f8230fb18da0efee0ea53da943e (presubmit successful).

[devoncarew, 2017-05-08 20:00:28]

lgtm