For the interim, may it be a wise idea to include an inlined script at the very top of any page which includes untrusted 3rd party code, in order to overwrite t

For the interim, may it be a wise idea to include an inlined script at the very top of any page which includes untrusted 3rd party code, in order to overwrite the Performance tools by a wrapper? By adding some random to the real numbers this may help mitigating effects ... E.g., (function() { var global = (function() { return this; }).call(), _Performance = global.Performance, _performance = global.performance; global.Performance = /* ... snip ... */; global.performance = /* ... snip ... */; })(); [Edit]: This could be injected by a browser-plugin on the user's side, as well.