https://bugs.webkit.org/show_bug.cgi?id=111894

Patch by Arpita Bahuguna <a.bah@samsung.com> on 2013-03-28
Reviewed by Ryosuke Niwa.

Source/WebCore:

There is a crash when trying to click/select an anonymous
renderer.

This is a regression due to r143313 which tries to add border/padding
to the computed caret rect in RenderBox::localCaretRect().
The patch calls on the node() method for the corresponding
renderer. For an anonymous renderer though, node() returns
null. Since no check had been added for this, a crash occurs when
caret rect for an anonymous renderer is being computed.

Test: editing/selection/click-on-anonymous-content-crash.html

* rendering/RenderBox.cpp:
(WebCore::RenderBox::localCaretRect):
Added a check for validating the return from the node() call.

LayoutTests:

* editing/selection/click-on-anonymous-content-crash-expected.txt: Added.
* editing/selection/click-on-anonymous-content-crash.html: Added.
Added a testcase for verifying that no crash occurs when trying to
select/click an anonymous renderer, in this case the list marker's
renderer.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@147087 268f45cc-cd09-0410-ab3c-d52691b4dbfc