Reviewed by Nate Chapin.

        [chromium] Provide a way to catch exceptions thrown while interacting
        with a NPObject via WebBindings methods.
        https://bugs.webkit.org/show_bug.cgi?id=39378

        This change also includes a small bit of cleanup in V8NPObject and
        friends.  I moved code into the WebCore namespace where appropriate.
        
        In _NPN_Invoke, I also moved the call to _NPN_Evaluate outside of the
        context scope.  I did this to avoid having nested ExceptionCatcher
        objects, which is not strictly necessary, but it seemed cleaner.
        _NPN_Evaluate already takes care of creating a context scope.

        * bindings/v8/NPV8Object.cpp:
        (WebCore::v8ObjectToNPObject):
        (WebCore::npCreateV8ScriptObject):
        (_NPN_Invoke):
        (_NPN_InvokeDefault):
        (_NPN_Evaluate):
        (_NPN_EvaluateHelper):
        (_NPN_GetProperty):
        (_NPN_SetProperty):
        (_NPN_RemoveProperty):
        (_NPN_HasProperty):
        (_NPN_HasMethod):
        (_NPN_SetException):
        (_NPN_Enumerate):
        (_NPN_Construct):
        * bindings/v8/NPV8Object.h:
        * bindings/v8/V8NPObject.cpp:
        * bindings/v8/V8NPObject.h:
        * bindings/v8/V8NPUtils.cpp:
        (WebCore::convertV8ObjectToNPVariant):
        (WebCore::pushExceptionHandler):
        (WebCore::popExceptionHandler):
        (WebCore::ExceptionCatcher::ExceptionCatcher):
        (WebCore::ExceptionCatcher::~ExceptionCatcher):
        * bindings/v8/V8NPUtils.h:
        * bindings/v8/npruntime.cpp:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@59862 268f45cc-cd09-0410-ab3c-d52691b4dbfc