Wires up immersive mode for chrome and mash

ash/common/frame/header_view.h

Index: ash/common/frame/header_view.h
diff --git a/ash/common/frame/header_view.h b/ash/common/frame/header_view.h
index 23657187352326aec39cd44d5fa43e5e761bd75c..a005f45a479cc273a74af9f5c1838cbee6b6fbf5 100644
--- a/ash/common/frame/header_view.h
+++ b/ash/common/frame/header_view.h
@@ -38,6 +38,8 @@ class ASH_EXPORT HeaderView : public views::View,
   explicit HeaderView(views::Widget* target_widget);
   ~HeaderView() override;
 
+  void set_is_immersive_delegate(bool value) { is_immersive_delegate_ = value; }
+
   // Schedules a repaint for the entire title.
   void SchedulePaintForTitle();
 
@@ -99,6 +101,9 @@ class ASH_EXPORT HeaderView : public views::View,
   // This value is meaningless when not in fullscreen.
   double fullscreen_visible_fraction_;
 
+  // Has this instance been set as the ImmersiveFullscreenControllerDelegate?
+  bool is_immersive_delegate_ = true;
+
   DISALLOW_COPY_AND_ASSIGN(HeaderView);
 };