https://bugs.webkit.org/show_bug.cgi?id=56901

Reviewed by Dimitri Glazkov.

Source/WebCore:

Test: fast/forms/interactive-validation-crash-by-style-override.html

* html/ValidationMessage.cpp:
(WebCore::ValidationMessage::buildBubbleTree): Add position:absolute
  because we need to move the validation message to a good position.
* rendering/RenderMenuList.cpp:
(WebCore::RenderMenuList::addChild):

LayoutTests:

* fast/forms/interactive-validation-crash-by-style-override-expected.txt: Added.
* fast/forms/interactive-validation-crash-by-style-override.html: Added.
* platform/gtk/Skipped: Skip the new test because the interactive
  validation feature is not enabled.
* platform/mac/Skipped: ditto.
* platform/qt/Skipped: ditto.
* platform/win/Skipped: ditto.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@81851 268f45cc-cd09-0410-ab3c-d52691b4dbfc