https://bugs.webkit.org/show_bug.cgi?id=122531

Reviewed by Geoffrey Garen.

The m_context field in ObjCCallbackFunctionImpl is vestigial and is only incidentally correct
in the common case. It's also no longer necessary in that we can look up the current JSContext
by looking using the globalObject of the callee when the function callback is invoked.

Also added a new test that would cause us to crash previously. The test required making
JSContextGetGlobalContext public API so that clients can obtain a JSContext from the JSContextRef
in C API callbacks.

* API/JSContextRef.h:
* API/JSContextRefPrivate.h:
* API/ObjCCallbackFunction.mm:
(JSC::ObjCCallbackFunctionImpl::ObjCCallbackFunctionImpl):
(JSC::objCCallbackFunctionCallAsFunction):
(objCCallbackFunctionForInvocation):
* API/WebKitAvailability.h:
* API/tests/CurrentThisInsideBlockGetterTest.h: Added.
* API/tests/CurrentThisInsideBlockGetterTest.mm: Added.
(CallAsConstructor):
(ConstructorFinalize):
(ConstructorClass):
(+[JSValue valueWithConstructorDescriptor:inContext:]):
(-[JSContext valueWithConstructorDescriptor:]):
(currentThisInsideBlockGetterTest):
* API/tests/testapi.mm:
* JavaScriptCore.xcodeproj/project.pbxproj:
* debugger/Debugger.cpp: Had to add some fully qualified names to avoid conflicts with Mac OS X headers.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@157468 268f45cc-cd09-0410-ab3c-d52691b4dbfc