Description

Before this change a RenderPointerListener that had active hover listeners (onPointerEnter, onPointerHover, onPointerExit) would drop any previous transforms on the floor if nobody else in that subtree required compositing. With this change RenderPointerListener itself now requests compositing if one of the hover listeners is set.

Debugging notes: If Nobody in a subtree requests compositing, the RenderTransform will execute the provided transform directly on the canvas instead of introducing a TransformLayer. When the RenderPointerListener pushes a new AnnotatedRegionLayer to make hover detection work, a new canvas for a new PictureLayer is created and all subsequent render objects draw into this new canvas, which doesn't know anything about the transform. Hence, the transform is ignored for all following draw operations.
If you push a layer, you need to request compositing to ensure that everything works correctly. Ideally, we should have an assert somewhere ensuring this.

Related Issues

Fixes #31986.

Tests

I added the following tests:

• A test to verify that RenderPointerListener with active hover listeners doesn't drop the transforms on the floor.

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Breaking Change

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