* **Electron Version** 4.0.4
* **Operating System** Windows 10 32 bit
* **Last known working Electron version** 3.1.3

### Expected Behavior
`webContents.print()` shold send print job to a printer

### Actual behavior
Nothing happens. Callback doesn't gets called. 

`printToPDF` works though.

### To Reproduce
```
let deviceName = 'HP LaserJet 1020'
let options = {deviceName, silent: true}
win.webContents.print({}, (err) => {
    if (!err)
      console.error('printing failed')
})
```

atom/browser/api/atom_api_web_contents.cc
auto* frame_host = web_contents()->GetMainFrame();
  if (!frame_host)
    return false;
  return frame_host->Send(new AtomFrameMsg_TakeHeapSnapshot(
      frame_host->GetRoutingID(),
      IPC::TakePlatformFileForTransit(std::move(file)), channel));
}
void WebContents::BuildPrototype(v8::Isolate* isolate,
                                 v8::Local<v8::FunctionTemplate> prototype) {
  prototype->SetClassName(mate::StringToV8(isolate, "WebContents"));
  mate::ObjectTemplateBuilder(isolate, prototype->PrototypeTemplate())
      .MakeDestroyable()
      .SetMethod("setBackgroundThrottling",
                 &WebContents::SetBackgroundThrottling)
      .SetMethod("getProcessId", &WebContents::GetProcessID)
      .SetMethod("getOSProcessId", &WebContents::GetOSProcessID)
      .SetMethod("equal", &WebContents::Equal)
      .SetMethod("_loadURL", &WebContents::LoadURL)
      .SetMethod("downloadURL", &WebContents::DownloadURL)
      .SetMethod("_getURL", &WebContents::GetURL)
      .SetMethod("getTitle", &WebContents::GetTitle)
      .SetMethod("isLoading", &WebContents::IsLoading)
      .SetMethod("isLoadingMainFrame", &WebContents::IsLoadingMainFrame)
      .SetMethod("isWaitingForResponse", &WebContents::IsWaitingForResponse)
      .SetMethod("_stop", &WebContents::Stop)
      .SetMethod("_goBack", &WebContents::GoBack)
      .SetMethod("_goForward", &WebContents::GoForward)
      .SetMethod("_goToOffset", &WebContents::GoToOffset)
      .SetMethod("isCrashed", &WebContents::IsCrashed)
      .SetMethod("setUserAgent", &WebContents::SetUserAgent)