Stop requiring NotificationAction action and title to be non-empty

Stop requiring NotificationAction action and title to be non-empty

Improve spec compliance. Note that
http/tests/notifications/serviceworkerregistration-document-actions-throw.html
still tests that they are set (but it's no longer possible to have an
equivalent check in NotificationDataTest, since required WebIDL
attributes are enforced at the V8 level by [1], and are bypassed when
creating IDL objects from C++).

[1]: https://chromium.googlesource.com/chromium/src/+/dfd8ec1b3edb7f876235bec1138ecec4f2da748d/third_party/WebKit/Source/bindings/templates/dictionary_v8.cpp#55

BUG=557624
Review URL: https://codereview.chromium.org/1487063002

Cr-Commit-Position: refs/heads/master@{#362469}
(cherry picked from commit 56c5368ca167742af3dfdd0bf8f879984b2ad05b)

Committed: https://chromium.googlesource.com/chromium/src/+/35bd3cd019fa030cad7500cd0d4c47d93d24333e

[johnme, 2015-12-03 17:15:37]

Description was changed from

==========
Stop requiring NotificationAction action and title to be non-empty

Improve spec compliance. Note that
http/tests/notifications/serviceworkerregistration-document-actions-throw.html
still tests that they are set (but it's no longer possible to have an
equivalent check in NotificationDataTest, since required WebIDL
attributes are enforced at the V8 level by [1], and are bypassed when
creating IDL objects from C++).

[1]:
https://chromium.googlesource.com/chromium/src/+/dfd8ec1b3edb7f876235bec1138e...

BUG=557624

Review URL: https://codereview.chromium.org/1487063002

Cr-Commit-Position: refs/heads/master@{#362469}
(cherry picked from commit 56c5368ca167742af3dfdd0bf8f879984b2ad05b)
==========

to

==========
Stop requiring NotificationAction action and title to be non-empty

Improve spec compliance. Note that
http/tests/notifications/serviceworkerregistration-document-actions-throw.html
still tests that they are set (but it's no longer possible to have an
equivalent check in NotificationDataTest, since required WebIDL
attributes are enforced at the V8 level by [1], and are bypassed when
creating IDL objects from C++).

[1]:
https://chromium.googlesource.com/chromium/src/+/dfd8ec1b3edb7f876235bec1138e...

BUG=557624

Review URL: https://codereview.chromium.org/1487063002

Cr-Commit-Position: refs/heads/master@{#362469}
(cherry picked from commit 56c5368ca167742af3dfdd0bf8f879984b2ad05b)

Committed:
https://chromium.googlesource.com/chromium/src/+/35bd3cd019fa030cad7500cd0d4c...
==========

[johnme, 2015-12-03 17:15:39]

Committed patchset #1 (id:1) manually as
35bd3cd019fa030cad7500cd0d4c47d93d24333e.