Reviewed by Adam Barth.

        Add a way to register V8 extensions for Isolated Worlds only.
        https://bugs.webkit.org/show_bug.cgi?id=27785

        * bindings/v8/ScriptController.cpp:
        (WebCore::ScriptController::evaluateInNewWorld):
        (WebCore::ScriptController::evaluateInNewContext):
        * bindings/v8/ScriptController.h:
        * bindings/v8/V8IsolatedWorld.cpp:
        (WebCore::V8IsolatedWorld::evaluate):
        * bindings/v8/V8IsolatedWorld.h:
        * bindings/v8/V8Proxy.cpp:
        (WebCore::V8Proxy::evaluateInNewWorld):
        (WebCore::V8Proxy::evaluateInNewContext):
        (WebCore::V8Proxy::createNewContext):
        (WebCore::V8Proxy::initContextIfNeeded):
        (WebCore::V8Proxy::registerExtensionWithV8):
        (WebCore::V8Proxy::registerExtension):
        * bindings/v8/V8Proxy.h:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@46594 268f45cc-cd09-0410-ab3c-d52691b4dbfc