react-native-maps: Memory leak on Android

Hi there,

I mount and unmount <MapView> component (with single marker) quite often. And during my test on real device the app is killed after some time by OS. I have investigated it more and found out that the memory usage is really high (I can get to 1.5GB after 25-30 cycles).

Applications Memory Usage (kB):
Uptime: 199716698 Realtime: 1702619320

** MEMINFO in pid 10768 [com.nativevibe] **
                   Pss  Private  Private  Swapped     Heap     Heap     Heap
                 Total    Dirty    Clean    Dirty     Size    Alloc     Free
                ------   ------   ------   ------   ------   ------   ------
  Native Heap        0        0        0        0    60402    60402    20493
  Dalvik Heap      165      104        0    82120   100544    84443    16101
 Dalvik Other        0        0        0      332                           
        Stack       68       68        0     1008                           
    Other dev   367039   366772       36        0                           
     .so mmap      409       12      148     2188                           
    .apk mmap       30        0        0        0                           
    .dex mmap       41        0        8        0                           
    code mmap      409        0        0        0                           
   image mmap      546       12        4     1876                           
   Other mmap       13        0        0        8                           
     Graphics    33444    33444        0        0                           
           GL   515760   515760        0        0                           
      Unknown      305      296        0    67744                           
        TOTAL   918229   916468      196   155276   160946   144845    36594

I am on Samsung S4 - Android 5.0.1. Quite funny is that same apk on different phone does not lead to such catastrophic results - the memory usage is still increasing but not in a such radical way.

Official documentation of GMap claims that the Users of this class must forward all the life cycle methods from the Activity or Fragment.

So I did make some experiments and I have added following code to AirMapManager

    @Override
    public void onDropViewInstance(AirMapView view) {
        super.onDropViewInstance(view);
        view.onDestroy();
    }

and it helped to significantly reduce the memory overhead - however the results were not perfect. However I don’t know if it is the “right” place to call such method since I don’t know the internals of react-native or to verify that onDestroy is really called since the method is final in AirMapView