function invalidateViewport(finishCallback)
        {
            if (this._needsFullUpdate) {
                this._updateMessageList();
                delete this._needsFullUpdate;
            } else {
                this._viewport.invalidate();
            }
            finishCallback();
        }
@param {!WebInspector.Throttler.FinishCallback} finishCallback
@this {WebInspector.ConsoleView}