Use new is*Element() helper functions in page/ code

Use new is*Element() helper functions in page/ code

Use new is*Element() helpers in page/ code. This makes the code clearer
and simpler.

R=eseidel, adamk
BUG=346095
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=169058

[Inactive, 2014-03-12 13:11:24]

ping review

[adamk, 2014-03-12 18:39:04]

lgtm

[Inactive, 2014-03-12 18:59:13]

The CQ bit was checked by ch.dumez@samsung.com

[commit-bot: I haz the power, 2014-03-12 19:31:10]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ch.dumez@samsung.com/190953009/1

[commit-bot: I haz the power, 2014-03-12 20:35:07]

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

[commit-bot: I haz the power, 2014-03-12 20:35:08]

Try jobs failed on following builders:
  tryserver.chromium on win_blink_rel

[Inactive, 2014-03-12 20:40:20]

The CQ bit was checked by ch.dumez@samsung.com

[commit-bot: I haz the power, 2014-03-12 20:40:33]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ch.dumez@samsung.com/190953009/1

[commit-bot: I haz the power, 2014-03-12 21:24:31]

Change committed as 169058