Crash on Android 7.0

[bmarty]

Reported by a user and found in the PlayStore report:

Today, 1:07 AM on app version 82100
Huawei P9 lite (HWVNS-H), Android 7.0

java.lang.NullPointerException: 
  at android.graphics.Canvas.<init> (Canvas.java:130)
  at im.vector.util.BitmapUtilKt.addBackgroundColor (BitmapUtil.kt:83)
  at im.vector.view.VectorCircularImageView$3.run (VectorCircularImageView.java:153)
  at android.os.Handler.handleCallback (Handler.java:761)
  at android.os.Handler.dispatchMessage (Handler.java:98)
  at android.os.Looper.loop (Looper.java:156)
  at android.os.HandlerThread.run (HandlerThread.java:61)