[wallet] Move getBlockHeight from Chain::Lock interface to simple Chain

Add HaveChain to assert chain access for wallet-tool in LoadToWallet.

src/interfaces/chain.cpp

@@ -55,15 +55,6 @@ bool FillBlock(const CBlockIndex* index, const FoundBlock& block, UniqueLock<Rec
 
 class LockImpl : public Chain::Lock, public UniqueLock<RecursiveMutex>
 {
-    Optional<int> getBlockHeight(const uint256& hash) override
-    {
-        LockAssertion lock(::cs_main);
-        CBlockIndex* block = LookupBlockIndex(hash);
-        if (block && ::ChainActive().Contains(block)) {
-            return block->nHeight;
-        }
-        return nullopt;
-    }
     uint256 getBlockHash(int height) override
     {
         LockAssertion lock(::cs_main);
@@ -234,6 +225,15 @@ public:
         }
         return nullopt;
     }
+    Optional<int> getBlockHeight(const uint256& hash) override
+    {
+        LOCK(::cs_main);
+        CBlockIndex* block = LookupBlockIndex(hash);
+        if (block && ::ChainActive().Contains(block)) {
+            return block->nHeight;
+        }
+        return nullopt;
+    }
     bool findBlock(const uint256& hash, const FoundBlock& block) override
     {
         WAIT_LOCK(cs_main, lock);

src/interfaces/chain.h

@@ -87,11 +87,6 @@ public:
     public:
         virtual ~Lock() {}
 
-        //! Get block height above genesis block. Returns 0 for genesis block,
-        //! 1 for following block, and so on. Returns nullopt for a block not
-        //! included in the current chain.
-        virtual Optional<int> getBlockHeight(const uint256& hash) = 0;
-
         //! Get block hash. Height must be valid or this function will abort.
         virtual uint256 getBlockHash(int height) = 0;
 
@@ -135,6 +130,11 @@ public:
     //! any blocks)
     virtual Optional<int> getHeight() = 0;
 
+    //! Get block height above genesis block. Returns 0 for genesis block,
+    //! 1 for following block, and so on. Returns nullopt for a block not
+    //! included in the current chain.
+    virtual Optional<int> getBlockHeight(const uint256& hash) = 0;
+
     //! Return whether node has the block and optionally return block metadata
     //! or contents.
     virtual bool findBlock(const uint256& hash, const FoundBlock& block={}) = 0;