React DevTools w/ Electron: Profiler "Reload and start profiling" doesn't work due to XMLHttpRequest 'null' origin

**Do you want to request a *feature* or report a *bug*?** An error gets thrown when using DevTools Profiler on **Electron** with the "**Reload and start profiling**" feature that leaves Profiler in an unexpected state - the profiling session does not end. I initially opened [the issue over at Electron](https://github.com/electron/electron/issues/20915), but [got asked to get your opinion first](https://github.com/electron/electron/issues/20915#issuecomment-548996868). **What is the current behavior?** - Open React DevTools Profiler in **Electron** - Click "Reload and start profiling" - Await reload - Do actions - Click "Stop profiling" - does not work - Because there are errors in console (actually thrown immediately after reload, don't have to do any extra actions): ``` Access to XMLHttpRequest at 'chrome-extension://react-developer-tools/build/renderer.js' from origin 'null' has been blocked by CORS policy: Cross origin requests are only supported for protocol schemes: http, data, chrome, https. ``` ``` Uncaught DOMException: Failed to execute 'send' on 'XMLHttpRequest': Failed to load 'chrome-extension://react-developer-tools/build/renderer.js'. ```   **If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem. Your bug will get fixed much faster if we can run your code and it doesn't have dependencies other than React. Paste the link to your JSFiddle (https://jsfiddle.net/Luktwrdm/) or CodeSandbox (https://codesandbox.io/s/new) example below:** You'll have to use [Electron Fiddle](https://github.com/electron/fiddle) for this one with this gist: https://gist.github.com/joltmode/82574cab4970def210dac0c68d4c34b8 **What is …