Resolve crash in FrameLoader::checkTimerFired.

Resolve crash in FrameLoader::checkTimerFired.
https://bugs.webkit.org/show_bug.cgi?id=77907

Patch by Chris Palmer <palmer@google.com> on 2012-02-07
Reviewed by Eric Seidel.

Source/WebCore:

Test is LayoutTests/http/tests/appcache/deferred-events-delete-while-raising-timer.html.

* loader/FrameLoader.cpp:
(WebCore::FrameLoader::checkTimerFired):

LayoutTests:

* http/tests/appcache/deferred-events-delete-while-raising-timer-expected.txt: Added.
* http/tests/appcache/deferred-events-delete-while-raising-timer.html: Added.
* http/tests/appcache/resources/deferred-events-delete-while-raising-timer-1.html: Added.
* http/tests/appcache/resources/deferred-events-delete-while-raising-timer-2.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@107023 268f45cc-cd09-0410-ab3c-d52691b4dbfc