wallet api/device: set estimated restore height if none is provided

src/wallet/api/wallet.cpp

@@ -942,6 +942,12 @@ uint64_t WalletImpl::approximateBlockChainHeight() const
 {
     return m_wallet->get_approximate_blockchain_height();
 }
+
+uint64_t WalletImpl::estimateBlockChainHeight() const
+{
+    return m_wallet->estimate_blockchain_height();
+}
+
 uint64_t WalletImpl::daemonBlockChainHeight() const
 {
     if(m_wallet->light_wallet()) {

src/wallet/api/wallet.h

@@ -109,6 +109,7 @@ public:
     uint64_t unlockedBalance(uint32_t accountIndex = 0) const override;
     uint64_t blockChainHeight() const override;
     uint64_t approximateBlockChainHeight() const override;
+    uint64_t estimateBlockChainHeight() const override;
     uint64_t daemonBlockChainHeight() const override;
     uint64_t daemonBlockChainTargetHeight() const override;
     bool synchronized() const override;

src/wallet/api/wallet2_api.h

@@ -574,6 +574,12 @@ struct Wallet
     */
     virtual uint64_t approximateBlockChainHeight() const = 0;
 
+    /**
+    * @brief estimateBlockChainHeight - returns estimate blockchain height. More accurate than approximateBlockChainHeight,
+    *                                   uses daemon height and falls back to calculation from date/time
+    * @return
+    **/ 
+    virtual uint64_t estimateBlockChainHeight() const = 0;
     /**
      * @brief daemonBlockChainHeight - returns daemon blockchain height
      * @return 0 - in case error communicating with the daemon.

src/wallet/api/wallet_manager.cpp

@@ -127,6 +127,8 @@ Wallet *WalletManagerImpl::createWalletFromDevice(const std::string &path,
     WalletImpl * wallet = new WalletImpl(nettype, kdf_rounds);
     if(restoreHeight > 0){
         wallet->setRefreshFromBlockHeight(restoreHeight);
+    } else {
+        wallet->setRefreshFromBlockHeight(wallet->estimateBlockChainHeight());
     }
     auto lookahead = tools::parse_subaddress_lookahead(subaddressLookahead);
     if (lookahead)