8244579: Windows "User Objects" leakage with WebView

[arun-joseph]

Cause: The Window Class RunLoopMessageWindow is never registered (this happens because registerRunLoopMessageWindowClass() is moved to MainThreadWin.cpp while openjfx uses MainThreadJava.cpp) and this causes every SetTimer() call in RunLoopWin.cpp to create a new user object instead of reusing the same object over again.

Fix: Call registerRunLoopMessageWindowClass() from MainThreadJava.cpp

Test: To verify open any webpage using WebView on WIndows, with and without the fix and compare the number of user objects created using Windows Task Manager.

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Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• Change must be properly reviewed

Issue

• JDK-8244579: Windows "User Objects" leakage with WebView

Reviewers

• Guru Hb (ghb - Reviewer)
• Kevin Rushforth (kcr - Reviewer)

Download

$ git fetch https://git.openjdk.java.net/jfx pull/229/head:pull/229
$ git checkout pull/229

[bridgekeeper]

👋 Welcome back ajoseph! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request.

[mlbridge]

Webrevs

• 00: Full (b883a45)

[kevinrushforth]

/reviewers 2

[openjdk]

@kevinrushforth
The number of required reviews for this PR is now set to 2 (with at least 1 of role reviewers).

[kevinrushforth]

Is there a way to create a test?

[arun-joseph]

I think it will be difficult to write a test for this. While debugging, RunLoop was mostly used by threads managing heap. It can't be directly accessed via JavaScript. Also, this issue only affects Windows. The best way would be to monitor the user objects created.

[johanvos]

https://bugs.openjdk.java.net/browse/JDK-8244579 refers to a manual test, but it's probably very hard to automate this.

[guruhb]

Looks good to me
Tested with your fix and ran Test case provided in JBS (WebViewUserObjectLeakage) didn't exceeds more than 50 user objects (Which is same as in 14-GA build).

[openjdk]

@arun-joseph This change now passes all automated pre-integration checks. When the change also fulfills all project specific requirements, type /integrate in a new comment to proceed. After integration, the commit message will be:

8244579: Windows "User Objects" leakage with WebView

Reviewed-by: ghb, kcr

• If you would like to add a summary, use the /summary command.
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Since the source branch of this PR was last updated there have been 2 commits pushed to the master branch:

• 37b5edc: 8245456: MacPasteboard throws ClassCastException on static builds
• 6e03930: 8237602: TabPane doesn't respect order of TabPane.getTabs() list

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid automatic rebasing, please merge master into your branch, and then specify the current head hash when integrating, like this: /integrate 37b5edc718c7538086938712f2d69ef4690c343a.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[arun-joseph]

/integrate

[openjdk]

@arun-joseph The following commits have been pushed to master since your change was applied:

• 37b5edc: 8245456: MacPasteboard throws ClassCastException on static builds
• 6e03930: 8237602: TabPane doesn't respect order of TabPane.getTabs() list

Your commit was automatically rebased without conflicts.

Pushed as commit a13a642.