fix: Removes messageQueue since produces memory leaks

[gmazzo]

Summary

Removes the (unnecessary?) private ConcurrentHashMap<Message, Boolean> messageQueue field and all its associated logic in BaseHandler, since it was identified by us (with LeakCanary) as the root cause of memory leaks when using DialogFragment.

After inspecting the whole code, that logic is a NO-OP since it's only used by AccessUtils.getUploadHandlerMessageQueue(), a method that is not getting called anywhere, probably a legacy code.

The leak is produced when a sendMessageAtTime method is invoked by AndroidX DialogFragment's internal logic. Since this specialized version of Handler stores Messages in a map, the whole tree is retained, producing the leak.

Unless we have missed something, messageQueue is not adding any value, therefore, there is no point in keeping it.

Note

Integration tests need to be cleanup as well mParticle/crossplatform-sdk-tests#44

LeakCanary report

┬───
│ GC Root: Thread object
│
├─ Ik instance
│    Leaking: NO (PathClassLoader↓ is not leaking)
│    Thread name: 'CleanupReference'
│    ↓ Thread.contextClassLoader
├─ dalvik.system.PathClassLoader instance
│    Leaking: NO (MParticle↓ is not leaking and A ClassLoader is never leaking)
│    ↓ ClassLoader.runtimeInternalObjects
├─ java.lang.Object[] array
│    Leaking: NO (MParticle↓ is not leaking)
│    ↓ Object[733]
├─ com.mparticle.MParticle class
│    Leaking: NO (a class is never leaking)
│    ↓ static MParticle.instance
│                       ~~~~~~~~
├─ com.mparticle.MParticle instance
│    Leaking: UNKNOWN
│    Retaining 129 B in 5 objects
│    mAppContext instance of com.glovoapp.HiltUiTestApp_Application
│    ↓ MParticle.mIdentityApi
│                ~~~~~~~~~~~~
├─ com.mparticle.identity.IdentityApi instance
│    Leaking: UNKNOWN
│    Retaining 16.7 kB in 577 objects
│    mContext instance of com.glovoapp.HiltUiTestApp_Application
│    ↓ IdentityApi.mMainHandler
│                  ~~~~~~~~~~~~
├─ com.mparticle.b instance
│    Leaking: UNKNOWN
│    Retaining 2.7 kB in 91 objects
│    ↓ b.c
│        ~
├─ java.util.concurrent.ConcurrentHashMap instance
│    Leaking: UNKNOWN
│    Retaining 2.7 kB in 90 objects
│    ↓ ConcurrentHashMap[key()]
│                       ~~~~~~~
├─ android.os.Message instance
│    Leaking: UNKNOWN
│    Retaining 2.5 kB in 87 objects
│    Message.what = 68
│    Message.when = 0 (6963473 ms before heap dump)
│    Message.obj = instance @322539720 of androidx.fragment.app.DialogFragment$2
│    Message.callback = null
│    Message.target = instance @322539736 of android.app.Dialog$ListenersHandler
│    ↓ Message.obj
│              ~~~
├─ androidx.fragment.app.DialogFragment$2 instance
│    Leaking: UNKNOWN
│    Retaining 2.4 kB in 84 objects
│    Anonymous class implementing android.content.DialogInterface$OnCancelListener
│    ↓ DialogFragment$2.this$0
│                       ~~~~~~
╰→ com.glovoapp.dialogs.OverlayProgressDialog instance
​     Leaking: YES (ObjectWatcher was watching this because com.glovoapp.dialogs.OverlayProgressDialog received Fragment#onDestroy() callback. Conflicts with Fragment.mLifecycleRegistry.state is INITIALIZED)
​     Retaining 2.4 kB in 83 objects
​     key = b09aba74-9150-412d-ab65-e56f4cd0efee
​     watchDurationMillis = 121257
​     retainedDurationMillis = 116245

522156 bytes retained by leaking objects
Signature: 05465ea5398979c4969c38a4a281600e9ab2b643

Testing Plan

• Was this tested locally? If not, explain why.
• Ran ./gradlew build locally and it has been successful.

[Mansi-mParticle]

LGTM

[mparticle-automation]

🎉 This PR is included in version 5.64.0 🎉

The release is available on GitHub release

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