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
bool menu_bar_visible_;
  bool menu_bar_alt_pressed_;
#if defined(USE_X11)
  std::unique_ptr<GlobalMenuBarX11> global_menu_bar_;
  
  std::unique_ptr<WindowStateWatcher> window_state_watcher_;
  
  std::unique_ptr<EventDisabler> event_disabler_;
  
  
  
  extensions::SizeConstraints old_size_constraints_;
#elif defined(OS_WIN)
  
  AtomDesktopWindowTreeHostWin* atom_desktop_window_tree_host_win_;
  ui::WindowShowState last_window_state_;
  
  
  
  
  gfx::Rect last_normal_bounds_;
  
  
  
  
  
  
  gfx::Rect last_normal_bounds_candidate_;
  bool consecutive_moves_;