Don't attribute a blob to a user if there are leasees from other users.

Bug: 187460239
Test: atest --test-mapping apex/blobstore
Change-Id: I5e9c0473e4c058d430ed012a3ca3ee63f3595821

apex/blobstore/service/java/com/android/server/blob/BlobMetadata.java

@@ -403,6 +403,19 @@ class BlobMetadata {
         return null;
     }
 
+    boolean shouldAttributeToUser(int userId) {
+        synchronized (mMetadataLock) {
+            for (int i = 0, size = mLeasees.size(); i < size; ++i) {
+                final Leasee leasee = mLeasees.valueAt(i);
+                // Don't attribute the blob to userId if there is a lease on it from another user.
+                if (userId != UserHandle.getUserId(leasee.uid)) {
+                    return false;
+                }
+            }
+        }
+        return true;
+    }
+
     boolean shouldAttributeToLeasee(@NonNull String packageName, int userId,
             boolean callerHasStatsPermission) {
         if (!isALeaseeInUser(packageName, INVALID_UID, userId)) {

apex/blobstore/service/java/com/android/server/blob/BlobStoreManagerService.java

@@ -1333,9 +1333,10 @@ public class BlobStoreManagerService extends SystemService {
                 blobsDataSize.getAndAdd(session.getSize());
             }, userHandle.getIdentifier());
 
-            // TODO(http://b/187460239): Update this to only include blobs available to userId.
             forEachBlob(blobMetadata -> {
-                blobsDataSize.getAndAdd(blobMetadata.getSize());
+                if (blobMetadata.shouldAttributeToUser(userHandle.getIdentifier())) {
+                    blobsDataSize.getAndAdd(blobMetadata.getSize());
+                }
             });
 
             stats.dataSize += blobsDataSize.get();