RFR: 8343630: Pass AccessControlContext to/from WebKit as opaque object

[Jay Bhaskar]

On Tue, 5 Nov 2024 17:57:19 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

> This PR modifies the signature of four methods -- 3 `native` JNI methods and 1 Java method that is called from native code using JNI -- changing the type of one of the arguments from `AccessControlContext` to `Object`.
> 
> As a follow-on to removing security manager support, we are removing all references to the terminally deprecated AccessController and AccessControlConext classes, which is tracked by [JDK-8342993](https://bugs.openjdk.org/browse/JDK-8342993).
> 
> The Java code passes an `AccessControlContext` instance to the native `JSObject` code, which stores it in the object so that it can later pass it back to the `Utilities::fwkInvokeWithContext` Java method via a JNI upcall. The native WebKit otherwise does not use the `AccessControlConext` object. Since it is already treated as an opaque object by the native code, the easiest path to eliminating the references to `AccessControlConext` is to change the method signatures to pass an `Object` rather than `AccessControlConext`. This has two related advantages:
> 
> 1. It will minimize the changes to native WebKit JNI code.
> 2. It will allow us to keep the native code identical between mainline jfx24 and earlier releases (e.g., jfx23u, jfx21u, etc), since earlier releases still need to be able to run with a security manager.
> 
> This bug fix needs to go in ahead of the fix for[JDK-8342993](https://bugs.openjdk.org/browse/JDK-8342993) and will be be backported to all earlier code lines (whereas none of the other SM follow-up fixes can be backported).
> 
> NOTE: Both this PR and PR #1620 touch the `Utilities::fwkInvokeWithContext` method. I did my fix in such a way that the two PRs can go in in either order with no conflicts. By doing it this way, it can be backported cleanly to earlier code lines. Consequently, after both PRs are integrated, there will be an unused local variable that can be removed. I will remove that as part of [JDK-8342993](https://bugs.openjdk.org/browse/JDK-8342993), along with the then-unneeded `SuppressWarnings` and unused `AccessController` import.

Looks good to me , tested via an example.

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Marked as reviewed by jbhaskar (Committer).

PR Review: https://git.openjdk.org/jfx/pull/1626#pullrequestreview-2424364177