wallet: Add input bytes to CInputCoin

With nInputBytes, coin selection can execute without a reference to the COutput

src/wallet/coinselection.h

@@ -28,12 +28,20 @@ public:
         effective_value = txout.nValue;
     }
 
+    CInputCoin(const CTransactionRef& tx, unsigned int i, int input_bytes) : CInputCoin(tx, i)
+    {
+        m_input_bytes = input_bytes;
+    }
+
     COutPoint outpoint;
     CTxOut txout;
     CAmount effective_value;
     CAmount fee = 0;
     CAmount long_term_fee = 0;
 
+    /** Pre-computed estimated size of this output as a fully-signed input in a transaction. Can be -1 if it could not be calculated */
+    int m_input_bytes{-1};
+
     bool operator<(const CInputCoin& rhs) const {
         return outpoint < rhs.outpoint;
     }

src/wallet/wallet.h

@@ -525,6 +525,11 @@ public:
     }
 
     std::string ToString() const;
+
+    inline CInputCoin GetInputCoin() const
+    {
+        return CInputCoin(tx->tx, i, nInputBytes);
+    }
 };