Add explicit return types to work around #29398.

Add explicit return types to work around #29398.

In a future CL I need to add an import to this file, and for reasons I
haven't been able to track down, doing so causes type inference
failures.  This CL works around the problem by making the affected
types explicit.

Once the bug is fixed, I hope to be able to revert this.

R=ahe@google.com

Committed: https://github.com/dart-lang/sdk/commit/b5c6053debe19699b1feb2167535c3e1f138e304

[Paul Berry, 2017-04-20 04:38:45]

paulberry@google.com changed reviewers:
+ ahe@google.com

[ahe, 2017-04-20 07:54:58]

lgtm

FWIW, I find it much easier to read when function signatures are fully typed, so
I'd prefer if we can avoid relying too much on type inference of function types.

In most cases, the inferred type is too specific.

[Paul Berry, 2017-04-20 08:29:57]

Description was changed from

==========
Add explicit return types to work around #29398.

In a future CL I need to add an import to this file, and for reasons I
haven't been able to track down, doing so causes type inference
failures.  This CL works around the problem by making the affected
types explicit.

Once the bug is fixed, I hope to be able to revert this.
==========

to

==========
Add explicit return types to work around #29398.

In a future CL I need to add an import to this file, and for reasons I
haven't been able to track down, doing so causes type inference
failures.  This CL works around the problem by making the affected
types explicit.

Once the bug is fixed, I hope to be able to revert this.

R=ahe@google.com

Committed:
https://github.com/dart-lang/sdk/commit/b5c6053debe19699b1feb2167535c3e1f138e304
==========

[Paul Berry, 2017-04-20 08:29:58]

Committed patchset #1 (id:1) manually as
b5c6053debe19699b1feb2167535c3e1f138e304 (presubmit successful).