electron: findInPage can freeze the whole app

Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for an issue that matches the one I want to file, without success.

Issue Details

• Electron Version:
  • 6.x
• Operating System:
  • macOS 10.14.6
• Last Known Working Electron version:
  • unknown

Expected Behavior

When one use webContents::findInPage method, it should not freeze the app.

Actual Behavior

On some verify specific conditions, it happens that calling webContents::findInPage can freeze the whole app. We are yet unsuccessful to reproduce the issue in Electron Fiddle. We haven’t found all the parameters that triggers the issues. I created this issue mainly to help us debug and be able to provide more information afterwards Additionnal information:

• found-in-page event is not received when it crashes
• ~The crash only happens in the first ~2seconds after the webContents in created. After that, no more freeze~ It can crash after those 2 seconds, but it’s not 100% of the time
• It can crash after the first findInPage call or subsequent ones (with or without findNext: true)
• We reproduce the issue with any webviews in our application 100% of the time
• We have multiple webviews behind each others
• We have multiple BrowserWindow (the visible one that crashes, and an invisible one)
• We tried to unplug all custom configuration on our webviews (no preload, all default webviews props), and we still have the crash
• As we only reproduce in our app, it is difficult to test with other Electron version than 6.x for now

To Reproduce

See comment above

Additional Information

See comment above