[net processing] Move ProcessHeadersMessage to PeerManager

src/net_processing.h

@@ -11,6 +11,7 @@
 #include <sync.h>
 #include <validationinterface.h>
 
+class CBlockHeader;
 class CChainParams;
 class CTxMemPool;
 class ChainstateManager;
@@ -90,6 +91,9 @@ private:
      */
     bool MaybeDiscourageAndDisconnect(CNode& pnode);
 
+    /** Process a single headers message from a peer. */
+    void ProcessHeadersMessage(CNode& pfrom, const std::vector<CBlockHeader>& headers, bool via_compact_block);
+
     const CChainParams& m_chainparams;
     CConnman& m_connman;
     /** Pointer to this node's banman. May be nullptr - check existence before dereferencing. */