core, eth, trie: prepare trie sync for path based operation

trie/secure_trie.go

@@ -79,6 +79,12 @@ func (t *SecureTrie) TryGet(key []byte) ([]byte, error) {
 	return t.trie.TryGet(t.hashKey(key))
 }
 
+// TryGetNode attempts to retrieve a trie node by compact-encoded path. It is not
+// possible to use keybyte-encoding as the path might contain odd nibbles.
+func (t *SecureTrie) TryGetNode(path []byte) ([]byte, int, error) {
+	return t.trie.TryGetNode(path)
+}
+
 // Update associates key with value in the trie. Subsequent calls to
 // Get will return value. If value has length zero, any existing value
 // is deleted from the trie and calls to Get will return nil.