https://bugs.webkit.org/show_bug.cgi?id=77593

Patch by Benjamin Poulain <bpoulain@apple.com> on 2012-02-02
Reviewed by Michael Saboff.

Source/JavaScriptCore: 

The method Interpreter::execute() was crashing on empty programs because
the assumption is made the source is not null.

This patch shortcut the execution when the String is null to avoid invalid
memory access.

* interpreter/Interpreter.cpp:
(JSC::Interpreter::execute):

LayoutTests: 

The Worker thread should not crash if running on an empty page.
The timer is necessary to give a chance for the thread to start.

* fast/workers/empty-worker-nocrash-expected.txt: Added.
* fast/workers/empty-worker-nocrash.html: Added.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@106600 268f45cc-cd09-0410-ab3c-d52691b4dbfc