Replace ASSERT by null-check in InsertedNodes::lastLeafInserted()

Replace ASSERT by null-check in InsertedNodes::lastLeafInserted()

Replace ASSERT by null-check in InsertedNodes::lastLeafInserted() as
m_lastNodeInserted can be null when this method is called. This ASSERT was
added in r161096 and we started hitting it in ClusterFuzz. This is also
consistent with InsertedNodes::pastLastLeaf() which already had a null
check.

R=adamk
BUG=338982
TEST=editing/execCommand/replaceSelectorCommand-crash.html

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=166065

[adamk, 2014-01-29 17:07:56]

This looks fine (and I'm excited that these reference conversions are actually
finding bugs). Ping back when you have the test attached.

[Inactive, 2014-01-29 20:11:24]

On 2014/01/29 17:07:56, adamk wrote:
> This looks fine (and I'm excited that these reference conversions are actually
> finding bugs). Ping back when you have the test attached.

I added the layout test. It really isn't easy to reduce and still be able to
reproduce the crash. Just adding text at the beginning of the file or using
js-test.js and it won't hit this ASSERT anymore.

[adamk, 2014-01-29 20:16:22]

lgtm

[commit-bot: I haz the power, 2014-01-29 20:20:42]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ch.dumez@samsung.com/149213006/20001

[commit-bot: I haz the power, 2014-01-29 23:58:56]

Change committed as 166065

[commit-bot: I haz the power, 2014-01-30 00:02:43]

CQ bit was unchecked on CL. Ignoring.