Remove redundant modifiers from safeTransferFrom (#1029) (#1030)

contracts/token/ERC721/ERC721BasicToken.sol

@@ -32,24 +32,6 @@ contract ERC721BasicToken is SupportsInterfaceWithLookup, ERC721Basic {
   // Mapping from owner to operator approvals
   mapping (address => mapping (address => bool)) internal operatorApprovals;
 
-  /**
-   * @dev Guarantees msg.sender is owner of the given token
-   * @param _tokenId uint256 ID of the token to validate its ownership belongs to msg.sender
-   */
-  modifier onlyOwnerOf(uint256 _tokenId) {
-    require(ownerOf(_tokenId) == msg.sender);
-    _;
-  }
-
-  /**
-   * @dev Checks msg.sender can transfer a token, by being owner, approved, or operator
-   * @param _tokenId uint256 ID of the token to validate
-   */
-  modifier canTransfer(uint256 _tokenId) {
-    require(isApprovedOrOwner(msg.sender, _tokenId));
-    _;
-  }
-
   constructor()
     public
   {
@@ -158,8 +140,8 @@ contract ERC721BasicToken is SupportsInterfaceWithLookup, ERC721Basic {
     uint256 _tokenId
   )
     public
-    canTransfer(_tokenId)
   {
+    require(isApprovedOrOwner(msg.sender, _tokenId));
     require(_from != address(0));
     require(_to != address(0));
 
@@ -188,7 +170,6 @@ contract ERC721BasicToken is SupportsInterfaceWithLookup, ERC721Basic {
     uint256 _tokenId
   )
     public
-    canTransfer(_tokenId)
   {
     // solium-disable-next-line arg-overflow
     safeTransferFrom(_from, _to, _tokenId, "");
@@ -213,7 +194,6 @@ contract ERC721BasicToken is SupportsInterfaceWithLookup, ERC721Basic {
     bytes _data
   )
     public
-    canTransfer(_tokenId)
   {
     transferFrom(_from, _to, _tokenId);
     // solium-disable-next-line arg-overflow