**Is your feature request related to a problem? Please describe.**
In windows tablet mode, you may want to change your UI. There is apps that enlarge the title bar or hide the title bar buttons since they are useless (in tablet mode, every window is forced into fullscreen mode and minimizing is disabled). The is no way to detect tablet mode in electron.

**Describe the solution you'd like**
~~Something like systemPreferences.tabletMode() and a `tablet-mode-changed` should be available~~
We need a BrowserWindow instance method like `window.getUserInteractionMode()` that gives us the primary input mode for a view. `window.resize` event should be sufficient to listen to changes to tablet mode. Here is more info: https://blogs.msdn.microsoft.com/oldnewthing/20160706-00/?p=93815

**Describe alternatives you've considered**
I looked into going to the Browser API  in renderer, but there is no clear way to check if a device is in tablet mode. You can basically just check if there is touch available, which is not the same.

**Additional context**
This is outlook hiding their title bar buttons in tablet mode.
<img width="850" alt="anmerkung" src="https://user-images.githubusercontent.com/4349324/46936928-42be3680-d060-11e8-8dfc-815ccac98e62.png">
<img width="849" alt="anmerkung2" src="https://user-images.githubusercontent.com/4349324/46936929-4356cd00-d060-11e8-8405-df5933e7cfbc.png">


shell/browser/native_window.h
virtual void SetSheetOffset(const double offsetX, const double offsetY);
  virtual double GetSheetOffsetX();
  virtual double GetSheetOffsetY();
  virtual void SetResizable(bool resizable) = 0;
  virtual bool MoveAbove(const std::string& sourceId) = 0;
  virtual void MoveTop() = 0;
  virtual bool IsResizable() = 0;
  virtual void SetMovable(bool movable) = 0;
  virtual bool IsMovable() = 0;
  virtual void SetMinimizable(bool minimizable) = 0;
  virtual bool IsMinimizable() = 0;
  virtual void SetMaximizable(bool maximizable) = 0;
  virtual bool IsMaximizable() = 0;
  virtual void SetFullScreenable(bool fullscreenable) = 0;
  virtual bool IsFullScreenable() = 0;
  virtual void SetClosable(bool closable) = 0;
  virtual bool IsClosable() = 0;
  virtual void SetAlwaysOnTop(ui::ZOrderLevel z_order,
                              const std::string& level = "floating",
                              int relativeLevel = 0) = 0;
  virtual ui::ZOrderLevel GetZOrderLevel() = 0;
  virtual void Center() = 0;
  virtual void Invalidate() = 0;
  virtual void SetTitle(const std::string& title) = 0;
  virtual std::string GetTitle() = 0;
  
  void SetAccessibleTitle(const std::string& title);
  std::string GetAccessibleTitle();
  virtual void FlashFrame(bool flash) = 0;
  virtual void SetSkipTaskbar(bool skip) = 0;