https://bugs.webkit.org/show_bug.cgi?id=116468

Reviewed by Andreas Kling.

Source/WebCore: 

Retain the node pointer. Also bail out early if the node was not in the document
since Range::compareBoundaryPoints sets ec to WRONG_DOCUMENT_ERR otherwise.

Test: editing/selection/contains-node-crash.html

* page/DOMSelection.cpp:
(WebCore::DOMSelection::containsNode):
* page/DOMSelection.h:
(DOMSelection):

LayoutTests: 

Add a regression test from https://chromium.googlesource.com/chromium/blink/+/40bb8089352b15dd034641b4c131111cd79b44f1.

* editing/selection/contains-node-crash-expected.txt: Added.
* editing/selection/contains-node-crash.html: Added.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@150498 268f45cc-cd09-0410-ab3c-d52691b4dbfc