[MC-79439] Loading player heads in offline mode causes game to freeze

The game freezes whenever it attempts to download a player's skin for the purposes of a player head texture when in offline mode. This happens not only when generating a player head item, but also when loading a player head as a block or an item.

My guess is that the code is not programmed to recognize that the client is in offline mode when trying to download a player skin for the head. This doesn't happen when trying to download the player's skin, so player heads should also default to a Steve skin when in offline mode.

I was playing in offline mode yesterday because the Internet connection at the house I just moved into had not been set up yet. Forgetting that I was offline, I used /give to get a player head. The specific command I used:

/give BoxFigs minecraft:skull 1 3 {SkullOwner:Chica_Chicken}

As soon as I ran the command, the game froze. It said "Not Responding" on the top. I closed it and relaunched. When I tried to load the world again, it was stuck in attempting to load the player head in my inventory. I closed the game again and used NBTExplorer to delete the head item.

I checked my log file, and this is what appeared when the game froze the first time:

[21:49:23] [Texture Downloader #1/ERROR]: Couldn't download http texture
java.net.ConnectException: Connection timed out: connect
	at java.net.TwoStacksPlainSocketImpl.socketConnect(Native Method) ~[?:1.8.0_31]
	at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source) ~[?:1.8.0_31]
	at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source) ~[?:1.8.0_31]
	at java.net.AbstractPlainSocketImpl.connect(Unknown Source) ~[?:1.8.0_31]
	at java.net.PlainSocketImpl.connect(Unknown Source) ~[?:1.8.0_31]
	at java.net.SocksSocketImpl.connect(Unknown Source) ~[?:1.8.0_31]
	at java.net.Socket.connect(Unknown Source) ~[?:1.8.0_31]
	at java.net.Socket.connect(Unknown Source) ~[?:1.8.0_31]
	at sun.net.NetworkClient.doConnect(Unknown Source) ~[?:1.8.0_31]
	at sun.net.www.http.HttpClient.openServer(Unknown Source) ~[?:1.8.0_31]
	at sun.net.www.http.HttpClient.openServer(Unknown Source) ~[?:1.8.0_31]
	at sun.net.www.http.HttpClient.<init>(Unknown Source) ~[?:1.8.0_31]
	at sun.net.www.http.HttpClient.New(Unknown Source) ~[?:1.8.0_31]
	at sun.net.www.http.HttpClient.New(Unknown Source) ~[?:1.8.0_31]
	at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(Unknown Source) ~[?:1.8.0_31]
	at sun.net.www.protocol.http.HttpURLConnection.plainConnect0(Unknown Source) ~[?:1.8.0_31]
	at sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown Source) ~[?:1.8.0_31]
	at sun.net.www.protocol.http.HttpURLConnection.connect(Unknown Source) ~[?:1.8.0_31]
	at bmb$1.run(SourceFile:106) [1.8.3.jar:?]

If it makes any difference, my laptop was wirelessly connected to the network, but the network wasn't connected to the Internet.