Implement forwards compatibility for summary enums.

Implement forwards compatibility for summary enums.

If an attempt is made to read an unrecognized enum value, then rather
than crashing, we will read the default (first) value of the enum type.

This facilitates forwards compatibility by ensuring that if a new enum
value is added in the future, older code will still be able to read the
resulting summary files without crashing.

R=scheglov@google.com

Committed: https://github.com/dart-lang/sdk/commit/ff6a744f38a2fa949c464d8fb9d52b3c7685bb5f

[Paul Berry, 2016-03-01 20:20:08]

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

[scheglov, 2016-03-01 20:22:15]

LGTM

[Paul Berry, 2016-03-01 21:28:13]

Description was changed from

==========
Implement forwards compatibility for summary enums.

If an attempt is made to read an unrecognized enum value, then rather
than crashing, we will read the default (first) value of the enum type.

This facilitates forwards compatibility by ensuring that if a new enum
value is added in the future, older code will still be able to read the
resulting summary files without crashing.
==========

to

==========
Implement forwards compatibility for summary enums.

If an attempt is made to read an unrecognized enum value, then rather
than crashing, we will read the default (first) value of the enum type.

This facilitates forwards compatibility by ensuring that if a new enum
value is added in the future, older code will still be able to read the
resulting summary files without crashing.

R=scheglov@google.com

Committed:
https://github.com/dart-lang/sdk/commit/ff6a744f38a2fa949c464d8fb9d52b3c7685bb5f
==========

[Paul Berry, 2016-03-01 21:28:15]

Committed patchset #1 (id:1) manually as
ff6a744f38a2fa949c464d8fb9d52b3c7685bb5f (presubmit successful).