Fix the full screen switching browser window dipping below launcher bar issue.

ui/aura/root_window.h

Index: ui/aura/root_window.h
diff --git a/ui/aura/root_window.h b/ui/aura/root_window.h
index b04857d1162eac1f149b3bff809ea1e1cb8c5e90..c8c322cd3e62e1778fd9ea58795a21ed96e9b3ef 100644
--- a/ui/aura/root_window.h
+++ b/ui/aura/root_window.h
@@ -73,7 +73,7 @@ class AURA_EXPORT RootWindow : public ui::CompositorDelegate,
   bool cursor_shown() const { return cursor_shown_; }
   Window* mouse_pressed_handler() { return mouse_pressed_handler_; }
   Window* capture_window() { return capture_window_; }
-  ScreenAura* screen() { return screen_; }
+  const ScreenAura* screen() { return screen_; }
 
   // Shows the root window host.
   void ShowRootWindow();
@@ -82,6 +82,9 @@ class AURA_EXPORT RootWindow : public ui::CompositorDelegate,
   void SetHostSize(const gfx::Size& size);
   gfx::Size GetHostSize() const;
 
+  // Sets the screen's work area insets, this notifies observers too.
+  void SetScreenWorkAreaInsets(const gfx::Insets& insets);
+
   // Sets the currently-displayed cursor. If the cursor was previously hidden
   // via ShowCursor(false), it will remain hidden until ShowCursor(true) is
   // called, at which point the cursor that was last set via SetCursor() will be