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("setFocusable", &Window::SetFocusable)
      .SetMethod("focusOnWebView", &Window::FocusOnWebView)
      .SetMethod("blurWebView", &Window::BlurWebView)
      .SetMethod("isWebViewFocused", &Window::IsWebViewFocused)
      .SetMethod("setProgressBar", &Window::SetProgressBar)
      .SetMethod("setOverlayIcon", &Window::SetOverlayIcon)
      .SetMethod("setThumbarButtons", &Window::SetThumbarButtons)
      .SetMethod("setMenu", &Window::SetMenu)
      .SetMethod("setAutoHideMenuBar", &Window::SetAutoHideMenuBar)
      .SetMethod("isMenuBarAutoHide", &Window::IsMenuBarAutoHide)
      .SetMethod("setMenuBarVisibility", &Window::SetMenuBarVisibility)
      .SetMethod("isMenuBarVisible", &Window::IsMenuBarVisible)
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      .SetMethod("isVisibleOnAllWorkspaces",
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#if defined(OS_WIN)
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      .SetMethod("isWindowMessageHooked", &Window::IsWindowMessageHooked)
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      .SetMethod("unhookAllWindowMessages", &Window::UnhookAllWindowMessages)
      .SetMethod("setThumbnailClip", &Window::SetThumbnailClip)
#endif
#if defined(TOOLKIT_VIEWS)
      .SetMethod("setIcon", &Window::SetIcon)
#endif
      .SetProperty("id", &Window::ID)
      .SetProperty("webContents", &Window::WebContents);
}
v8::Local<v8::Value> Window::From(v8::Isolate* isolate,