Delete a blob after the last lease of it is released.

Also, avoid deleting it if it was committed recently
to allow app that contributed it to acquire a lease.

Bug: 151378266
Test: atest --test-mapping apex/blobstore
Change-Id: I32f9bc0d0e9d74e7a07c279b5057f53ccb610673

tests/BlobStoreTestUtils/src/com/android/utils/blob/DummyBlobData.java

@@ -46,7 +46,7 @@ public class DummyBlobData {
     byte[] mFileDigest;
     long mExpiryTimeMs;
 
-    public DummyBlobData(Builder builder) {
+    private DummyBlobData(Builder builder) {
         mRandom = new Random(builder.getRandomSeed());
         mFile = new File(builder.getContext().getFilesDir(), builder.getFileName());
         mFileSize = builder.getFileSize();

tests/BlobStoreTestUtils/src/com/android/utils/blob/Utils.java

@@ -124,7 +124,11 @@ public class Utils {
         final BlobStoreManager blobStoreManager = (BlobStoreManager) context.getSystemService(
                 Context.BLOB_STORE_SERVICE);
         blobStoreManager.releaseLease(blobHandle);
-        assertThat(blobStoreManager.getLeaseInfo(blobHandle)).isNull();
+        try {
+            assertThat(blobStoreManager.getLeaseInfo(blobHandle)).isNull();
+        } catch (SecurityException e) {
+            // Expected, ignore
+        }
     }
 
     private static void assertLeaseInfo(LeaseInfo leaseInfo, String packageName,