chain: expose coins methods.

lib/blockchain/chain.js

@@ -1739,6 +1739,21 @@ Chain.prototype.getOrphan = function getOrphan(hash) {
   return this.orphan.bmap[hash] || null;
 };
 
+/**
+ * Get coin viewpoint.
+ * @param {TX} tx
+ * @returns {Promise} - Returns {@link CoinView}.
+ */
+
+Chain.prototype.getCoinView = co(function* getCoinView(tx) {
+  var unlock = yield this.locker.lock();
+  try {
+    return yield this.db.getCoinView(tx);
+  } finally {
+    unlock();
+  }
+});
+
 /**
  * Test the chain to see if it is synced.
  * @returns {Boolean}