RFR: 8334137: Marlin: replace sun.misc.Unsafe memory access methods with FFM [v8]

[Kevin Rushforth]

On Wed, 11 Jun 2025 17:30:48 GMT, Andy Goryachev <angorya at openjdk.org> wrote:

>> Kevin Rushforth has updated the pull request incrementally with two additional commits since the last revision:
>> 
>>  - Use the global arena for the ALPHA_MASK arrays.
>>  - Revert "Initialize alpha maps in constructor to ensure they are created on the right thread (QuantumRenderer)"
>>    
>>    This reverts commit 2dd7a35d2eec16b04de1f4cb7aeba31be5d98a55.
>
> modules/javafx.graphics/src/main/java/com/sun/marlin/OffHeapArray.java line 59:
> 
>> 57:      */
>> 58:     OffHeapArray(final Object parent, final long len) {
>> 59:         this(parent, len, false);
> 
> I would suggest to remove this constructor.

Since global is the special case, it seemed easier to keep the existing constructor and only pass "global=true" in the one place that's needed -- the static initializer of `MaskMarlinAlphaConsumer`.

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PR Review Comment: https://git.openjdk.org/jfx/pull/1814#discussion_r2140748003