RFR: 8244579: Windows "User Objects" leakage with WebView

[Guru Hb]

On Wed, 20 May 2020 14:30:11 GMT, Arun Joseph <ajoseph at openjdk.org> wrote:

> 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](https://github.com/openjdk/jfx/blob/master/modules/javafx.web/src/main/native/Source/WTF/wtf/win/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.

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).

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Marked as reviewed by ghb (Reviewer).

PR: https://git.openjdk.java.net/jfx/pull/229