Call PaintLayer::setNeedsRepaint in LayoutBoxModelObject::invalidateDisplayItemClientOnBacking()

Call PaintLayer::setNeedsRepaint in LayoutBoxModelObject::invalidateDisplayItemClientOnBacking()

To ensure layer is set needsRepaint().

BUG=536999
TEST=scrollbars/scrollbar-added-during-drag.html etc with sync painting enabled

Committed: https://crrev.com/4c9d4570c68eddbc58f73b1fb4f4c95614bcf9d3
Cr-Commit-Position: refs/heads/master@{#361179}

[Xianzhu, 2015-11-23 19:02:42]

wangxianzhu@chromium.org changed reviewers:
+ chrishtr@chromium.org

[Xianzhu, 2015-11-23 19:03:31]

This is one of the last 2 CLs before we can try to enable sync painting again.

[chrishtr, 2015-11-23 19:03:54]

The CQ bit was checked by chrishtr@chromium.org

[chrishtr, 2015-11-23 19:03:54]

lgtm

[commit-bot: I haz the power, 2015-11-23 19:07:04]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1469823004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1469823004/1

[commit-bot: I haz the power, 2015-11-23 20:42:39]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-23 20:44:07]

Patchset 1 (id:??) landed as
https://crrev.com/4c9d4570c68eddbc58f73b1fb4f4c95614bcf9d3
Cr-Commit-Position: refs/heads/master@{#361179}

[Xianzhu, 2015-11-24 17:19:22]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1475483003/ by wangxianzhu@chromium.org.

The reason for reverting is: This is incorrect. We missed setNeedsRepaint() of
the PaintLayers between the object's enclosingLayer and
paintInvalidationContainer's layer..