interfaces: Add isChange to wallet interface

Author: achow101

src/interfaces/wallet.h

@@ -124,6 +124,9 @@ class Wallet
     //! Save or remove receive request.
     virtual bool setAddressReceiveRequest(const CTxDestination& dest, const std::string& id, const std::string& value) = 0;
 
+    //! Whether the given output is a change
+    virtual bool isChange(const CTxOut& txout) const = 0;
+
     //! Display address on external signer
     virtual bool displayAddress(const CTxDestination& dest) = 0;
 

src/wallet/interfaces.cpp

@@ -245,6 +245,11 @@ class WalletImpl : public Wallet
         return value.empty() ? m_wallet->EraseAddressReceiveRequest(batch, dest, id)
                              : m_wallet->SetAddressReceiveRequest(batch, dest, id, value);
     }
+    bool isChange(const CTxOut& txout) const override
+    {
+        LOCK(m_wallet->cs_wallet);
+        return OutputIsChange(*m_wallet, txout);
+    }
     bool displayAddress(const CTxDestination& dest) override
     {
         LOCK(m_wallet->cs_wallet);