- Electron version: 1.2.2
- Operating system: Linux

This is a problem only in linux. It works in OSX.

``` javascript
win.hide()
win.capturePage(function(img){
 // never called
})
```

shell/browser/api/electron_api_web_contents.cc
#include "shell/browser/extensions/electron_extension_ontents_observer.h"
#endif
#if BUILDFLAG(ENABLE_PRINTING)
#include "chrome/browser/printing/print_view_manager_basic.h"
#include "components/printing/browser/print_manager_utils.h"
#include "printing/backend/print_backend.h"  
#include "printing/mojom/print.mojom.h"
#include "shell/browser/printing/print_preview_message_handler.h"
#if defined(OS_WIN)
#include "printing/backend/win_helper.h"
#endif
#endif
#if BUILDFLAG(ENABLE_COLOR_CHOOSER)
#include "chrome/browser/ui/color_chooser.h"
#endif
#if BUILDFLAG(ENABLE_PICTURE_IN_PICTURE)
#include "chrome/browser/picture_in_picture/picture_in_picture_window_manager.h"
#endif
#if BUILDFLAG(ENABLE_PDF_VIEWER)
#include "components/pdf/browser/pdf_ontents_helper.h"  
#include "shell/browser/electron_pdf_ontents_helper_client.h"
#endif
#ifndef MAS_BUILD
#include "chrome/browser/hang_monitor/hang_crash_dump.h"  
#endif
namespace gin {
#if BUILDFLAG(ENABLE_PRINTING)
template <>
struct Converter<printing::mojom::MarginType> {
  static bool FromV8(v8::Isolate* isolate,