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/native_window_views.h
void FlashFrame(bool flash) override;
  void SetSkipTaskbar(bool skip) override;
  void SetKiosk(bool kiosk) override;
  bool IsKiosk() override;
  void SetBackgroundColor(const std::string& color_name) override;
  void SetHasShadow(bool has_shadow) override;
  bool HasShadow() override;
  void SetIgnoreMouseEvents(bool ignore) override;
  void SetContentProtection(bool enable) override;
  void SetFocusable(bool focusable) override;
  void SetMenu(AtomMenuModel* menu_model) override;
  void SetParentWindow(NativeWindow* parent) override;
  gfx::NativeWindow GetNativeWindow() override;
  void SetOverlayIcon(const gfx::Image& overlay,
                      const std::string& description) override;
  void SetProgressBar(double value) override;
  void SetAutoHideMenuBar(bool auto_hide) override;
  bool IsMenuBarAutoHide() override;
  void SetMenuBarVisibility(bool visible) override;
  bool IsMenuBarVisible() override;
  void SetVisibleOnAllWorkspaces(bool visible) override;
  bool IsVisibleOnAllWorkspaces() override;
  gfx::AcceleratedWidget GetAcceleratedWidget() override;
#if defined(OS_WIN)
  void SetIcon(HICON small_icon, HICON app_icon);
#elif defined(USE_X11)
  void SetIcon(const gfx::ImageSkia& icon);
#endif
  void SetEnabled(bool enable);
  views::Widget* widget() const { return window_.get(); }