Support [Replaceable] for screen, pageXOffset, pageYOffset

Support [Replaceable] for screen, pageXOffset, pageYOffset

This updates screen, pageXOffset, pageYOffset to match changes to
the CSSOM View spec[1]. 

[1] http://dev.w3.org/csswg/cssom-view/#extensions-to-the-window-interface

BUG=474472
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=193798

[Abhijeet Kandalkar Slow, 2015-04-13 11:40:45]

abhijeet.k@samsung.com changed reviewers:
+ philipj@opera.com, vivekg@chromium.org

[Abhijeet Kandalkar Slow, 2015-04-13 11:41:56]

Please review patch.

[zcorpan, 2015-04-13 13:46:28]

Can remove this:

// FIXME: None of the CCSOM View Module attributes should be [Replaceable].

[philipj_slow, 2015-04-15 11:28:09]

LGTM if the FIXME is removed. I can't find a reason to suspect that this change
would break stuff.

[Abhijeet Kandalkar Slow, 2015-04-15 13:11:45]

Review comments are incorporated.

[Abhijeet Kandalkar Slow, 2015-04-15 13:12:43]

The CQ bit was checked by abhijeet.k@samsung.com to run a CQ dry run

[Abhijeet Kandalkar Slow, 2015-04-15 13:12:43]

The patchset sent to the CQ was uploaded after l-g-t-m from philipj@opera.com
Link to the patchset: https://codereview.chromium.org/1087493002/#ps20001
(title: " ")

[commit-bot: I haz the power, 2015-04-15 13:12:50]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1087493002/20001

[commit-bot: I haz the power, 2015-04-15 15:44:59]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-04-15 15:45:00]

This issue passed the CQ dry run.

[Abhijeet Kandalkar Slow, 2015-04-15 16:04:20]

The CQ bit was checked by abhijeet.k@samsung.com

[commit-bot: I haz the power, 2015-04-15 16:06:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1087493002/20001

[commit-bot: I haz the power, 2015-04-15 16:07:29]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=193798