- Electron version: 1.3.6
- Operating system: Windows 7 x64
- Other: Microsoft Office 2013 (will make more sense in a bit)

`shell.openItem()` is a blocking call, it would be nice if it's async or has an async version to handle synchronous external application behavior.

Reproduce: 
Open a password-protected Microsoft Excel file, `shell.openItem()` will be blocking until the Password window is submitted or dismissed. Consequently Microsoft Word does not have this issue.

Related to #2761.

shell/browser/ui/inspectable_web_contents_impl.cc
return point.x() > rect.x() && point.x() < (rect.width() + rect.x()) &&
         point.y() > rect.y() && point.y() < (rect.height() + rect.y());
}
bool IsPointInScreen(const gfx::Point& point) {
  for (const auto& display : display::Screen::GetScreen()->GetAllDisplays()) {
    if (IsPointInRect(point, display.bounds()))
      return true;
  }
  return false;
}
void SetZoomLevelForWebContents(content::WebContents* web_contents,
                                double level) {
  content::HostZoomMap::SetZoomLevel(web_contents, level);
}
double GetNextZoomLevel(double level, bool out) {
  double factor = blink::PageZoomLevelToZoomFactor(level);
  size_t size = base::size(kPresetZoomFactors);
  for (size_t i = 0; i < size; ++i) {
    if (!blink::PageZoomValuesEqual(kPresetZoomFactors[i], factor))
      continue;
    if (out && i > 0)
      return blink::PageZoomFactorToZoomLevel(kPresetZoomFactors[i - 1]);
    if (!out && i != size - 1)
      return blink::PageZoomFactorToZoomLevel(kPresetZoomFactors[i + 1]);
  }
  return level;
}
GURL GetRemoteBaseURL() {