Enable shelf gestures in immersive mode

ash/shelf/shelf_layout_manager.h

Index: ash/shelf/shelf_layout_manager.h
diff --git a/ash/shelf/shelf_layout_manager.h b/ash/shelf/shelf_layout_manager.h
index d074e65b474f64e1cbe5d28867e427ec8d2ee9b0..e2018f8eaa181fd9f452a39f03aa242b07b1bb37 100644
--- a/ash/shelf/shelf_layout_manager.h
+++ b/ash/shelf/shelf_layout_manager.h
@@ -184,6 +184,10 @@ class ASH_EXPORT ShelfLayoutManager :
   // Is the shelf's alignment horizontal?
   bool IsHorizontalAlignment() const;
 
+  // Tests if the browser is currently in fullscreen mode with minimal
+  // Chrome. When minimal Chrome is present the shelf should be displayed.
+  bool FullscreenWithMinimalChrome() const;
+
   // Returns a ShelfLayoutManager on the display which has a launcher for
   // given |window|. See RootWindowController::ForLauncher for more info.
   static ShelfLayoutManager* ForLauncher(aura::Window* window);