TxConfidenceTable: new method getConfidence(Transaction)

Use it in `Wallet`.

core/src/main/java/org/bitcoinj/core/TxConfidenceTable.java

@@ -92,6 +92,15 @@ public class TxConfidenceTable {
         this(MAX_SIZE);
     }
 
+    /**
+     * Get the confidence object for a transaction
+     * @param tx the transaction
+     * @return the corresponding confidence object
+     */
+    public TransactionConfidence getConfidence(Transaction tx) {
+        return tx.getConfidence(this);
+    }
+
     /**
      * If any transactions have expired due to being only weakly reachable through us, go ahead and delete their
      * table entries - it means we downloaded the transaction and sent it to various event listeners, none of

core/src/main/java/org/bitcoinj/wallet/Wallet.java

@@ -4502,7 +4502,7 @@ public class Wallet extends BaseTaggableObject
     }
 
     private TransactionConfidence getConfidence(Transaction tx) {
-        return tx.getConfidence(Context.get().getConfidenceTable());
+        return Context.get().getConfidenceTable().getConfidence(tx);
     }
 
     /**