mac: Refer to NSEvent scrollingDeltaY as a method.

mac: Refer to NSEvent scrollingDeltaY as a method.

Prior to OSX 10.10, the declaration is a method. In OSX 10.10, the declaration
became a property. For simplicity and consistent, always refer to
scrollingDeltaY as a method.

BUG=471823
Committed: https://crrev.com/8ea365b4d2f7747a765b531edc5c57ccf3ee317f
Cr-Commit-Position: refs/heads/master@{#327437}

[erikchen, 2015-04-28 23:53:58]

erikchen@chromium.org changed reviewers:
+ mark@chromium.org

[erikchen, 2015-04-28 23:53:59]

mark: Please review.

[Mark Mentovai, 2015-04-29 00:37:28]

LGTM

[erikchen, 2015-04-29 01:26:51]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2015-04-29 01:27:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1116563002/1

[commit-bot: I haz the power, 2015-04-29 05:08:44]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-29 05:09:46]

Patchset 1 (id:??) landed as
https://crrev.com/8ea365b4d2f7747a765b531edc5c57ccf3ee317f
Cr-Commit-Position: refs/heads/master@{#327437}