Remove use of GetCountWithDescendants in wallet code

This commit does not change behavior.

src/interfaces/chain.cpp

@@ -190,6 +190,12 @@ public:
         LOCK(::mempool.cs);
         return IsRBFOptIn(tx, ::mempool);
     }
+    bool hasDescendantsInMempool(const uint256& txid) override
+    {
+        LOCK(::mempool.cs);
+        auto it_mp = ::mempool.mapTx.find(txid);
+        return it_mp != ::mempool.mapTx.end() && it_mp->GetCountWithDescendants() > 1;
+    }
 };
 
 } // namespace

src/interfaces/chain.h

@@ -135,6 +135,9 @@ public:
 
     //! Check if transaction is RBF opt in.
     virtual RBFTransactionState isRBFOptIn(const CTransaction& tx) = 0;
+
+    //! Check if transaction has descendants in mempool.
+    virtual bool hasDescendantsInMempool(const uint256& txid) = 0;
 };
 
 //! Interface to let node manage chain clients (wallets, or maybe tools for

src/wallet/feebumper.cpp

@@ -27,9 +27,7 @@ static feebumper::Result PreconditionChecks(interfaces::Chain::Lock& locked_chai
     }
 
     {
-        LOCK(mempool.cs);
-        auto it_mp = mempool.mapTx.find(wtx.GetHash());
-        if (it_mp != mempool.mapTx.end() && it_mp->GetCountWithDescendants() > 1) {
+        if (wallet->chain().hasDescendantsInMempool(wtx.GetHash())) {
             errors.push_back("Transaction has descendants in the mempool");
             return feebumper::Result::INVALID_PARAMETER;
         }