ASSERTION FAILED: !object || object->isTable()

ASSERTION FAILED: !object || object->isTable()

The issue is caused by call sites of
RenderBlock::addChildIgnoringAnonymousColumnBlocks
that basically bypass the RenderTable::addChild logic causing
all sorts of mayhem. The fix I decided on is to fix the previous
RenderBlock function as it's the safest approach to the current
madness.

This change adds an extra ASSERT into RenderObjectChildList to
catch further problem earlier.

BUG=309421
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=164125

[Julien - ping for review, 2013-12-13 19:51:17]

Work-around a very old bug, this should make our multi-column anonymous renderer
splitting madness less crazy.

[leviw_travelin_and_unemployed, 2013-12-17 00:17:56]

I've just been in this code, too. Sad, but lgtm. Thanks, sir!

https://codereview.chromium.org/111873005/diff/1/LayoutTests/fast/table/bad-t...
File LayoutTests/fast/table/bad-table-insert-anonymous-multi-column-expected.txt
(right):

https://codereview.chromium.org/111873005/diff/1/LayoutTests/fast/table/bad-t...
LayoutTests/fast/table/bad-table-insert-anonymous-multi-column-expected.txt:1: 
The "test passes if no crash" thing isn't in the output?

[Julien - ping for review, 2013-12-18 21:32:47]

https://codereview.chromium.org/111873005/diff/1/LayoutTests/fast/table/bad-t...
File LayoutTests/fast/table/bad-table-insert-anonymous-multi-column-expected.txt
(right):

https://codereview.chromium.org/111873005/diff/1/LayoutTests/fast/table/bad-t...
LayoutTests/fast/table/bad-table-insert-anonymous-multi-column-expected.txt:1: 
On 2013/12/17 00:17:56, Levi wrote:
> The "test passes if no crash" thing isn't in the output?

Yeah, I wish I could add it to the output but the test does several editing
rounds and it's unclear to me how to get it dumped.

[commit-bot: I haz the power, 2013-12-18 21:33:02]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jchaffraix@chromium.org/111873005/1

[commit-bot: I haz the power, 2013-12-18 23:45:06]

Change committed as 164125