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.h
void BlurWebView();
  bool IsWebViewFocused();
  void SetRepresentedFilename(const std::string& filename);
  std::string GetRepresentedFilename();
  void SetDocumentEdited(bool edited);
  bool IsDocumentEdited();
  void SetIgnoreMouseEvents(bool ignore);
  void SetContentProtection(bool enable);
  void SetFocusable(bool focusable);
  void SetProgressBar(double progress);
  void SetOverlayIcon(const gfx::Image& overlay,
                      const std::string& description);
  bool SetThumbarButtons(mate::Arguments* args);
  void SetMenu(v8::Isolate* isolate, v8::Local<v8::Value> menu);
  void SetAutoHideMenuBar(bool auto_hide);
  bool IsMenuBarAutoHide();
  void SetMenuBarVisibility(bool visible);
  bool IsMenuBarVisible();
  void SetAspectRatio(double aspect_ratio, mate::Arguments* args);
  void SetParentWindow(v8::Local<v8::Value> value, mate::Arguments* args);
  v8::Local<v8::Value> GetParentWindow() const;
  std::vector<v8::Local<v8::Object>> GetChildWindows() const;
  bool IsModal() const;
  v8::Local<v8::Value> GetNativeWindowHandle();
#if defined(OS_WIN)
  typedef base::Callback<void(v8::Local<v8::Value>,
                              v8::Local<v8::Value>)> MessageCallback;
  bool HookWindowMessage(UINT message, const MessageCallback& callback);
  bool IsWindowMessageHooked(UINT message);
  void UnhookWindowMessage(UINT message);