Try disabling Network Service via chrome://flags/#network-service

I've disabled it, but this had no effect on the issue - neither for my extension, nor other proxy extensions.

Thanks for filing the issue!

@Reporter: Could you please share a sample test file(extension), which helps us to triage this further in a better way.

Hi! Took a while to setup reproducible code sample. Here's a repository: https://github.com/Mindaugas-Jacionis/proxy-extension-mvp

You can git clone it and follow the Readme instructions, that way you can reproduce the bug and extension has minimal code needed to reproduce it.

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Tried testing the issue as per comment#5, when we tried loading the extension it says "Failed to load extension". Attaching the screenshot of the same for reference.

@Reporter: Could you please have a look at the screenshot and let us know if anything is being missed from our end.

Thanks!

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	919101.png 315 KB View Download

I assume you're selecting the root directory of the project. You should be opening the one named "src", as this is where the extension(including manifest.json) files are

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Tried checking the issue on reported chrome version 71.0.3578.98  using Mac 10.14.1 by selecting the root directory of the project named "src" from extension provided in Comment#5 & as per comment#8, could add the extension successfully. Then clicked on extension icon -> Connect.
Restarted the browser(using command + Q)
Observed No auth prompted. 

As we are checking this on an open network and this seems to be specific to Proxy Network, hence adding label "TE-NeedsTriageHelp" and requesting someone from "Internals>Network>Proxy" team to help in triaging it further.

Thanks!

This is odd, everyone on the team can reproduce the issue(this makes 12/12 people on different platforms). 
Before quitting do you see the proxy set in chrome://settings > Advanced > System > Proxy Settings? 
Is VirtualBox on with the local proxy server? After you click connect you should be able to use internet just fine if local proxy server is ON. If it is OFF(or not set up) you'll end-up with no internet connection after clicking "Connect". Instructions on how to setup local proxy server that uses authentication are in Readme.md file. 

Any flags you have enabled or disabled on your browser that might affect this? Or is it default browser setup? 

My (uneducated) guess is that the extension to set the proxy is loading first, so we're showing a dialog before the one to send credentials is loaded, which would make this pretty dependent on various performance characteristics (Latency to proxy, storage performance, etc).  Or does it pop up more than once?

To my experience it pops only once, when browser is being initialized. As mentioned earlier, this is new behavior since 71st version and affects all proxy extensions that provide auth based service(tested that to validate).
This behaviour was not apparent in any older browsers or another extension that we have  released 1.5years ago and since then was working as intended until recent version of the browser when it started "misbehaving" as well. That is the reason I believe this to be a regression.

My guess is: extension sets proxy settings, those are saved in chrome settings(even can be seen on chrome://settings > advanced > system > proxy). These settings are persisted as in any older version of chrome and once browser is restarted, traffic is directed based on those settings as they are persisted, though extension is that controls this(or any other extension for that matter) is yet initialized by the browser. 


Persisting proxy settings of course is a good thing as it helps to avoid any leaks, but if any extension is responsible for those settings would be nice to initialize that extension beforehand(at least that's my guess is why any older version worked like a charm). :)