GameObjectContext pool memory leak fix. Todo: cover by test

[kkohno]

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• [x] Tests for the changes have been added (for bug fixes / features)
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• [x] Bugfix
• [ ] Feature
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Issue Number: #118

What is the new behavior?

only failing test

Does this introduce a breaking change?

• [ ] Yes
• [x] No

Other information

On real case it work fine, when my system frequently reloads the scenes, but test are fails. I not sure, that this test available at all, because .Net Garbage Collector has no exact dispose method call time (correct me, if i am not right)...

On which Unity version has this been tested?

• [ ] 2020.4 LTS
• [ ] 2020.3
• [x] 2020.2
• [ ] 2020.1
• [ ] 2019.4 LTS
• [ ] 2019.3
• [ ] 2019.2
• [ ] 2019.1
• [ ] 2018.4 LTS

Scripting backend:

• [x] Mono
• [x] IL2CPP

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[kkohno]

Seems that StaticMemoryPoolRegistry is cause of leaks. It is only Editor feature. But in some cases it is big trouble. For example - the scanning anti-cheat system for editor...

[kkohno]

Maybe WeakReference is key to solve this:

StaticMemoryPoolRegistry.cs:

namespace Zenject
{
#if UNITY_EDITOR
    public static class StaticMemoryPoolRegistry
    {
        public static event Action<IMemoryPool> PoolAdded = delegate {};
        public static event Action<IMemoryPool> PoolRemoved = delegate {};

        readonly static List<WeakReference> _pools = new List<WeakReference>();

        public static IEnumerable<WeakReference> Pools
        {
            get { return _pools; }
        }

        public static void Add(IMemoryPool memoryPool)
        {
            _pools.Add(new WeakReference(memoryPool));
            PoolAdded(memoryPool);
        }

        public static void Remove(IMemoryPool memoryPool)
        {
            _pools.RemoveWithConfirm(new WeakReference(memoryPool));
            PoolRemoved(memoryPool);
        }
    }
#endif
}

[kkohno]

yes, my code is working... but i changed MpmView.cs too, for output correct pools and exclude memory leaks. I can make pool request