ash/immersive mode: Hide the launcher when entering immersive mode

ash/root_window_controller.h

Index: ash/root_window_controller.h
diff --git a/ash/root_window_controller.h b/ash/root_window_controller.h
index 92185a6a63ea562a710909c986e80f1c80074848..e5e85ef1e24b76279b611199ae5cb36e7a8667cd 100644
--- a/ash/root_window_controller.h
+++ b/ash/root_window_controller.h
@@ -164,6 +164,10 @@ class ASH_EXPORT RootWindowController {
   bool SetShelfAlignment(ShelfAlignment alignment);
   ShelfAlignment GetShelfAlignment();
 
+  // Returns true if the active workspace is in immersive mode. Exposed here
+  // so clients of Ash don't need to know the details of workspace management.
+  bool IsImmersiveMode() const;
+
  private:
   // Creates each of the special window containers that holds windows of various
   // types in the shell UI.