8374804: ConditionalFeature media queries

[mstr2]

This PR adds the -fx-supports-conditional-feature media query, which allows applications to adapt their stylesheets to different platforms with varying conditional feature support. Currently, the built-in themes use hard-coded logic to include or exclude conditional-feature stylesheets. The new media query allows us to potentially remove the hard-coded logic in the future, and gives third-party themes an API to query conditional feature support.

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Progress

• Change must not contain extraneous whitespace
• Change requires CSR request JDK-8384139 to be approved
• Commit message must refer to an issue
• Change must be properly reviewed (2 reviews required, with at least 1 Reviewer, 1 Author)

Issues

• JDK-8374804: ConditionalFeature media queries (Enhancement - P4)
• JDK-8384139: ConditionalFeature media queries (CSR)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jfx.git pull/2161/head:pull/2161
$ git checkout pull/2161

Update a local copy of the PR:
$ git checkout pull/2161
$ git pull https://git.openjdk.org/jfx.git pull/2161/head

Using Skara CLI tools

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$ git pr checkout 2161

View PR using the GUI difftool:
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Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back mstrauss! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

The total number of required reviews for this PR has been set to 2 based on the presence of this label: rfr. This can be overridden with the /reviewers command.

[mstr2]

/reviewers 2

[openjdk]

@mstr2
The total number of required reviews for this PR (including the jcheck configuration and the last /reviewers command) is now set to 2 (with at least 1 Reviewer, 1 Author).

[mlbridge]

Webrevs

• 00: Full (f8ebff5e)

[mstr2]

/csr

[openjdk]

@mstr2 has indicated that a compatibility and specification (CSR) request is needed for this pull request.

@mstr2 please create a CSR request for issue JDK-8374804 with the correct fix version. This pull request cannot be integrated until the CSR request is approved.

[kevinrushforth]

This looks like a nice addition. I'll review the CSR, but I hope others will review the code.

Reviewers: @andy-goryachev-oracle , ???

[andy-goryachev-oracle]

yes, it's in my review queue