[AaronFriel]

That part of the code doesn't exist in a vacuum, and it's baked in at a rather low level in the browser. That's how it can block requests! In JavaScript!

Google will begin by deprecating the webRequest block API (that's in progress). Then they will begin deprecating the code that supports it.

Then they will begin removing and deleting the "unnecessary" code. Then, at some point in the future, they may make other breaking changes to the webRequest flow that assume that requests cannot be blocked. Each time Google writes new code that assumes webRequests cannot be blocked, Microsoft must patch that code too.

With each successive change, Microsoft will be forced to make a choice:

1. Support both Google's webRequest API and the Microsoft's, at increasing cost with every merge and rebase where Google has cut off or altered another piece of functionality

2. Adopt Google's API and break ad blockers

Google has a profit motive in shrinking the ad blocking market, and therefore they have a perverse incentive to make their browser worse for users, and more expensive for any forks that want to maintain ad blocking functionality.

[Aeolun]

Ostensibly Microsofts browser team is the size of Googles’. They could just fork once and never look back.

Merging incompatible changes seems like a win compared to doing everything themselves.

[benatkin]

That's what Apple did by forking KHTML and starting the Webkit project. KHTML is still maintained and both KHTML and Webkit can be used in KDE.

[halter73]

And even more recently with Blink forking WebKit.

[notatoad]

as long as they're still supporting that API in enterprise installs, they're going to have a difficult time deprecating the code that drives it

[AaronFriel]

Google Chrome Enterprise didn't exist when Manifest version 2 was introduced (and version 1 deprecated), so it's difficult to guess what will happen this time around. But if the policy now is the same as then, here's what will occur:

Chrome will deprecate in a release, approximately 1 year later Chrome will block updating of any extensions using the old manifest, and after approximately 18 months they will remove any extensions from the Web Store that have not updated, and approximately 2 years after the deprecation later the code to support the manifest will be removed.