We can get the content size and the window size, but not the chrome position.

At the moment we do this:

```
leftBorderWidth = (windowWidth - contentWidth) / 2;
titlebarHeight = windowHeight - (contentHeight + leftBorderWidth);
```

which makes some assumptions so therefore feels a bit wrong.

it would be nice if alongside getContentSize (https://github.com/electron/electron/blob/master/docs/api/browser-window.md#wingetcontentsize) there was a getContentOffset.

I've been looking at the C++ - https://github.com/electron/electron/blob/e05804848f98959d63337aacd9047cd579c5b23f/chromium_src/extensions/browser/app_window/size_constraints.cc and I don't see an easy way to get this information - do you have any ideas or pointers if you accept this as a feature request?

atom/browser/api/atom_api_window.cc
.SetMethod("setMovable", &Window::SetMovable)
      .SetMethod("isMovable", &Window::IsMovable)
      .SetMethod("setMinimizable", &Window::SetMinimizable)
      .SetMethod("isMinimizable", &Window::IsMinimizable)
      .SetMethod("setMaximizable", &Window::SetMaximizable)
      .SetMethod("isMaximizable", &Window::IsMaximizable)
      .SetMethod("setFullScreenable", &Window::SetFullScreenable)
      .SetMethod("isFullScreenable", &Window::IsFullScreenable)
      .SetMethod("setClosable", &Window::SetClosable)
      .SetMethod("isClosable", &Window::IsClosable)
      .SetMethod("setAlwaysOnTop", &Window::SetAlwaysOnTop)
      .SetMethod("isAlwaysOnTop", &Window::IsAlwaysOnTop)
      .SetMethod("center", &Window::Center)
      .SetMethod("setPosition", &Window::SetPosition)
      .SetMethod("getPosition", &Window::GetPosition)
      .SetMethod("setTitle", &Window::SetTitle)
      .SetMethod("getTitle", &Window::GetTitle)
      .SetMethod("flashFrame", &Window::FlashFrame)
      .SetMethod("setSkipTaskbar", &Window::SetSkipTaskbar)
      .SetMethod("setKiosk", &Window::SetKiosk)
      .SetMethod("isKiosk", &Window::IsKiosk)
      .SetMethod("setBackgroundColor", &Window::SetBackgroundColor)
      .SetMethod("setHasShadow", &Window::SetHasShadow)
      .SetMethod("hasShadow", &Window::HasShadow)
      .SetMethod("setRepresentedFilename", &Window::SetRepresentedFilename)
      .SetMethod("getRepresentedFilename", &Window::GetRepresentedFilename)
      .SetMethod("setDocumentEdited", &Window::SetDocumentEdited)
      .SetMethod("isDocumentEdited", &Window::IsDocumentEdited)
      .SetMethod("setIgnoreMouseEvents", &Window::SetIgnoreMouseEvents)
      .SetMethod("setContentProtection", &Window::SetContentProtection)