[webcomponents] Closed flag proposal breaks ability to audit and automate tests of web pages (#354)

If web components are created with the closed flag and these web components create interactive elements within their shadow DOM, it is not possible for auditing tools to check for the validity of that markup.

Two examples of auditing that are useful and currently being done

1. Accessibility auditing
2. Standards compliance auditing (HTML spec, ARIA spec)

In addition, if a user of that component wishes to use automation tools like Selenium to automate the testing of that component, it is not possible to interact with the shadow DOM components.

Both of these problems present major obstacles to efficient development of quality web applications and therefore represent a failure on the part of this specification to enhance and ease the development of quality, interactive web applications.

There are two potential solutions:

1. Remove this closed flag altogether
2. Expose the composed tree through a set of APIs that will allow automation and auditing to occur regardless of the closed/open mode. This should include an API to efficiently discover and return the DOM nodes that have a shadow root and should allow for querySelector* to operate within this composed tree.

If the browser vendors are in favor of 2, I would volunteer to write a proposal


---
Reply to this email directly or view it on GitHub:
https://github.com/w3c/webcomponents/issues/354