- Electron version: 1.2.2, and 1.3.1 (I only tested the 2 versions)
- Operating system: Windows 10

steps:

1.　Register a  custom protocol **`"app"`** by `protocol.registerFileProtocol`

```
    protocol.registerStandardSchemes(['app']);
    app.on('ready', function(){
        protocol.registerFileProtocol('app', (request, callback) => {
            //.......
        });
        //.......
    });
```

2.　call `cookies.set` for **`app://myhost/`**

```
    session.defaultSession.cookies.set({
            url : 'app://myhost/',      //custom protocol
            name : 'test',
            value : '12345'
        },
        (error)=>{
            if(error){
                console.log(error);  //error occurred here
            }
        }
    );
```

With url of custom protocol, an error will occur.  

If using standard http protocol, the code works well.

```
    session.defaultSession.cookies.set({
            url : 'http://otherhost/',     //standard http protocol
            name : 'test',
            value : '12345'
        },
        (error)=>{  //works well, no error
            if(error){
                console.log(error);
            }
        }
    );
```

atom/browser/api/atom_api_protocol.cc
#include "atom/browser/api/atom_api_protocol.h"
#include "atom/browser/atom_browser_client.h"
#include "atom/browser/atom_browser_main_parts.h"
#include "atom/browser/browser.h"
#include "atom/browser/net/url_request_async_asar_job.h"
#include "atom/browser/net/url_request_buffer_job.h"
#include "atom/browser/net/url_request_fetch_job.h"
#include "atom/browser/net/url_request_string_job.h"
#include "atom/common/native_mate_converters/callback.h"
#include "atom/common/native_mate_converters/value_converter.h"
#include "atom/common/node_includes.h"
#include "atom/common/options_switches.h"
#include "base/command_line.h"
#include "base/strings/string_util.h"
#include "content/public/browser/child_process_security_policy.h"
#include "native_mate/dictionary.h"
#include "url/url_util.h"
using content::BrowserThread;
namespace atom {
namespace api {
namespace {
void ClearJobFactoryInIO(