There's no simple, cross-platform way to register protocol handlers in Electron. Every OS requires a different solution. This seems like something that Electron should smooth over.

There's already a W3C API for this: [`Navigator.registerProtocolHandler`](https://developer.mozilla.org/en-US/docs/Web/API/Navigator/registerProtocolHandler). Can Electron implement it?

atom/browser/browser_win.cc
DWORD target_process_id = *reinterpret_cast<DWORD*>(param);
  DWORD process_id = 0;
  GetWindowThreadProcessId(hwnd, &process_id);
  if (process_id == target_process_id) {
    SetFocus(hwnd);
    return FALSE;
  }
  return TRUE;
}
}  
void Browser::Focus() {
  
  DWORD pid = GetCurrentProcessId();
  EnumWindows(&WindowsEnumerationHandler, reinterpret_cast<LPARAM>(&pid));
}
void Browser::AddRecentDocument(const base::FilePath& path) {
  if (base::win::GetVersion() < base::win::VERSION_WIN7)
    return;
  CComPtr<IShellItem> item;
  HRESULT hr = SHCreateItemFromParsingName(
      path.value().c_str(), NULL, IID_PPV_ARGS(&item));
  if (SUCCEEDED(hr)) {
    SHARDAPPIDINFO info;
    info.psi = item;
    info.pszAppID = GetAppUserModelID();
    SHAddToRecentDocs(SHARD_APPIDINFO, &info);
  }
}
void Browser::ClearRecentDocuments() {