Problem

I want to inherit ERC721Full.sol contract and add an extra getter for an array of tokens held by a given user.

Expected behaviour

In previous versions it was possible by adding an extra function and accessing an internal _ownedTokens mapping:

function tokensOfOwner(address _owner) external view returns (uint256[]) {
    return ownedTokens[_owner];
}

Current behaviour

In version 2.x it is impossible to access a private _ownedTokens mapping.