* Output of `node_modules/.bin/electron --version`: 2.0.12
* Operating System (Platform and Version): macOS 10.14

**Expected Behavior**
When having a window in simple fullscreen and you change display metrics or change from 1 monitor to 2 the window should size according to the new dimensions.

**Actual behavior**
The window size does not change when display metrics change.

**To Reproduce**
* Run Fiddle: https://gist.github.com/bpasero/e4013ea83033a8c231f58f94c0df57c3
* Change display metrics or change monitor count

=> the window is wrongly sized now and needs a transition from normal back to fullscreen to recover.
shell/browser/native_window.h
virtual bool GetWindowButtonVisibility() const = 0;
  virtual void SetTrafficLightPosition(base::Optional<gfx::Point> position) = 0;
  virtual base::Optional<gfx::Point> GetTrafficLightPosition() const = 0;
  virtual void RedrawTrafficLights() = 0;
#endif
  
  virtual void SetTouchBar(std::vector<gin_helper::PersistentDictionary> items);
  virtual void RefreshTouchBarItem(const std::string& item_id);
  virtual void SetEscapeTouchBarItem(gin_helper::PersistentDictionary item);
  
  virtual void SelectPreviousTab();
  virtual void SelectNextTab();
  virtual void MergeAllWindows();
  virtual void MoveTabToNewWindow();
  virtual void ToggleTabBar();
  virtual bool AddTabbedWindow(NativeWindow* window);
  
  virtual void SetAutoHideMenuBar(bool auto_hide);
  virtual bool IsMenuBarAutoHide();
  virtual void SetMenuBarVisibility(bool visible);
  virtual bool IsMenuBarVisible();
  
  double GetAspectRatio();
  gfx::Size GetAspectRatioExtraSize();
  virtual void SetAspectRatio(double aspect_ratio, const gfx::Size& extra_size);
  
  virtual void PreviewFile(const std::string& path,
                           const std::string& display_name);
  virtual void CloseFilePreview();
  virtual void SetGTKDarkThemeEnabled(bool use_dark_theme) {}