Reviewed by Darin.

    Reviewed by Darin.

        - Fixed <rdar://problem/4430836> JavaScript patch crashing Quartz
        Composer

        JSValueWrappers used to hold on to the ExecState that pertained at
        the time of their creation. Since ExecStates are transient, that
        design was totally bogus, and it would crash once the ExecState had
        been deallocated.

        Unfortunately, there's no clean solution to this problem, since
        the JSGlue API has no notion of state. The solution here is to use
        a shared, global ExecState for the purpose of JSGlue calls. Given
        the pre-existing limitations in the JSGlue API, this design
        shouldn't actually introduce any new limitations (see comments in
        JSValueWrapper.cpp).

        I tested with Quartz Composer and PAC files, neither of which are
        layout-testable.

        * JSUtils.cpp:
        (KJSValueToJSObject):
        * JSValueWrapper.cpp:
        (JSValueWrapper::JSValueWrapper):
        (JSValueWrapper::GetValue):
        (getProcessGlobalExecState):
        (JSValueWrapper::JSObjectCopyPropertyNames):
        (JSValueWrapper::JSObjectCopyProperty):
        (JSValueWrapper::JSObjectSetProperty):
        (JSValueWrapper::JSObjectCallFunction):
        (JSValueWrapper::JSObjectCopyCFValue):
        * JSValueWrapper.h:

        Also added a test harness file. It was helpful while I was testing,
        and may come in handy in the future:

        * JavaScriptGlue.xcodeproj/project.pbxproj:
        testjsglue.cpp: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@13635 268f45cc-cd09-0410-ab3c-d52691b4dbfc