Memory leak

[underworld9]

this is a follow up Issue to #413
While the memory leak of Issue 413 is fixed there are still objects which allocation count rises with each session.
Details:

I have found a memory leak when closing a session. (stopping & destroying the ArCore activity)
found using the Android Profiler.
Total memory has increased. There are some objects with names like "bfs", "bao", "arz", etc. that get increased by 1 after a session was opened.
The allocation count starts at 3 so in the first session the allocation count is 3 in the next 4 and so on.
So after opening a session 3 times these objects have an allocation count of 5.
note: the object with name "bys" is always 3 times the number and "bpa" is always double.

First session:

3rd session:

11th session:

this is tested in HelloScenform sample and other ArCore apps.
the memory leak happens every time the Activity is destroyed.
it never happens if the Activity is saved and stopped.

the increase in memory is much smaller with 1.7 than it was in 1.6 thanks to the fix in #413 i assume.

[artemtkachenko]

@underworld9

I am experiencing the same issue.
The hellosceneform profile results. I launched and finished several HelloSceneformActivities one by one. And all of the objects: Camera Texture Scene remains in memory after forcing GC:
https://monosnap.com/file/ewEPKAHXgPRDQRo6JhGRwCuXhcZutl
These objects holds an an ArSceneView that is why HelloSceneformActivitiy leaked.

Moreover I found that with using asyncPause() feature my Pixel3 reports an error:

E/ACameraDevice: onDeviceIdle sending state cb
E/ActivityThread: Activity %app_package_my_activity% has leaked ServiceConnection apy@e18bb27 that was originally bound here
android.app.ServiceConnectionLeaked: Activity %app_package_my_activity% has leaked ServiceConnection apy@e18bb27 that was originally bound here
at android.app.LoadedApk$ServiceDispatcher.<init>(LoadedApk.java:1610)
at android.app.LoadedApk.getServiceDispatcher(LoadedApk.java:1502)
at android.app.ContextImpl.bindServiceCommon(ContextImpl.java:1659)
at android.app.ContextImpl.bindService(ContextImpl.java:1612)
at android.content.ContextWrapper.bindService(ContextWrapper.java:698)
at com.google.ar.core.services.AnalyticsClient.bindService(PG:30)
at com.google.ar.core.Session.nativeCreateSessionWithFeatures(Native Method)
at com.google.ar.core.Session.<init>(Session.java:23)

It seems that all the samples and scene-form itself was not designed for releasing resources.