Fix RenderBlock::percentHeightDescendants()

Fix RenderBlock::percentHeightDescendants()

RenderBlock::percentHeightDescendants() is used to schedule layout of
descencents of a block when the logical height of the block changes.
It should contain descendants having percent height whose real height
calculation depends on the height of the block.

Previously
- the set doesn't contain direct children;
- skipped containing blocks for percent height calculation unnecessarily
  have the set.

Let the set contain all necessary objects. This doesn't fix any
functional breakage for now, but later layout optimization may depend
on the correct behavior of the function.

BUG=327815
TEST=WebFrameTest.RenderBlockPercentHeightDescendants

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=169588

[Xianzhu, 2014-03-17 21:54:39]

This CL is split from https://codereview.chromium.org/190973007/ which needs
more thinking.

[ojan, 2014-03-19 20:06:00]

lgtm

[commit-bot: I haz the power, 2014-03-19 20:06:04]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/wangxianzhu@chromium.org/201153008/1

[commit-bot: I haz the power, 2014-03-19 21:21:45]

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

[commit-bot: I haz the power, 2014-03-19 21:21:45]

Try jobs failed on following builders:
  tryserver.blink on linux_blink_dbg

[pdr., 2014-03-19 21:35:01]

The CQ bit was checked by pdr@chromium.org

[commit-bot: I haz the power, 2014-03-19 21:36:34]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/wangxianzhu@chromium.org/201153008/1

[commit-bot: I haz the power, 2014-03-19 22:51:32]

Change committed as 169588