Corner cases handling.

- crash on disappearing dataloaders,
- more robust binder callbacks processing,
- heavy unbind lifting moved to a separate thread to unblock Binder.

Bug: b/153874006
Test: atest PackageManagerShellCommandTest PackageManagerShellCommandIncrementalTest IncrementalServiceTest
Change-Id: Ie06c3c4dbecbdd552dd868e2092bf0ee48f8547a
diff --git a/services/incremental/IncrementalService.h b/services/incremental/IncrementalService.h
index 1de0070..81fbe74 100644
--- a/services/incremental/IncrementalService.h
+++ b/services/incremental/IncrementalService.h
@@ -179,6 +179,7 @@
         binder::Status onStatusChanged(MountId mount, int newStatus) final;
 
         bool isValid() const { return mId != kInvalidStorageId; }
+        sp<content::pm::IDataLoader> getDataLoader();
 
         bool bind();
         bool create();