Invalidate background-attachment:fixed on scroll.

Invalidate background-attachment:fixed on scroll.

If there is any slow repaint objects (i.e. background-attachment:fixed),
we fall back to the FrameView::scrollContentsSlowPath() that invalidates
the whole main graphics layer. However this is not correct because the
object is not necessarily backed by the main backing. We should invalidate
them individually.

Note: This approach is still not entirely correct. With composited overflow
scrolling, we should inhibit threaded scrolling when a slow repaint descandant
presents and do similar invalidation. This is non-trivial to implement.
As the old compositing architecture is deprecated anyway, we will try to fix
the issue with SPv2.

BUG=540499
Committed: https://crrev.com/1d3aacc9cd5028db3a36036bfbace8933097be00
Cr-Commit-Position: refs/heads/master@{#354960}

[trchen, 2015-10-09 02:43:56]

The CQ bit was checked by trchen@chromium.org to run a CQ dry run

[trchen, 2015-10-09 02:44:24]

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

[commit-bot: I haz the power, 2015-10-09 02:44:57]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1394193003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1394193003/1

[commit-bot: I haz the power, 2015-10-09 03:46:23]

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

[commit-bot: I haz the power, 2015-10-09 03:46:23]

Dry run: Try jobs failed on following builders:
  win_chromium_rel_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[Xianzhu, 2015-10-12 16:05:51]

https://codereview.chromium.org/1394193003/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/layout/LayoutObject.cpp (left):

https://codereview.chromium.org/1394193003/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/layout/LayoutObject.cpp:3433: void
LayoutObject::setIsSlowRepaintObject(bool isSlowRepaintObject)
Can you also rename this function and
LayoutBox::updateSlowRepaintStatusAfterStyleChange()?

[chrishtr, 2015-10-16 19:56:06]

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

[chrishtr, 2015-10-16 19:56:06]

I found another report of this in the wild, and dup'ed it against this bug. Can
you please commit this ASAP? We should merge it into M47.

[trchen, 2015-10-17 01:51:53]

The CQ bit was checked by trchen@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-10-17 01:52:02]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1394193003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1394193003/20001

[commit-bot: I haz the power, 2015-10-17 02:59:27]

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

[commit-bot: I haz the power, 2015-10-17 02:59:28]

Dry run: This issue passed the CQ dry run.

[Xianzhu, 2015-10-20 01:19:55]

The CQ bit was checked by wangxianzhu@chromium.org

[Xianzhu, 2015-10-20 01:19:55]

lgtm

[commit-bot: I haz the power, 2015-10-20 01:20:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1394193003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1394193003/20001

[commit-bot: I haz the power, 2015-10-20 02:39:41]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-10-20 02:40:28]

Patchset 2 (id:??) landed as
https://crrev.com/1d3aacc9cd5028db3a36036bfbace8933097be00
Cr-Commit-Position: refs/heads/master@{#354960}