Wires up immersive mode for chrome and mash

chrome/browser/ui/views/frame/immersive_mode_controller_ash.h

Index: chrome/browser/ui/views/frame/immersive_mode_controller_ash.h
diff --git a/chrome/browser/ui/views/frame/immersive_mode_controller_ash.h b/chrome/browser/ui/views/frame/immersive_mode_controller_ash.h
index 599752410abc30f6c34a99a1ca67e1c5d9c9376d..4427bff06884f4d64a43a1a4f050cb38688739da 100644
--- a/chrome/browser/ui/views/frame/immersive_mode_controller_ash.h
+++ b/chrome/browser/ui/views/frame/immersive_mode_controller_ash.h
@@ -20,6 +20,8 @@ namespace aura {
 class Window;
 }
 
+// See ash/mus/frame/README.md for description of how immersive mode works in
+// mash. This code works with both classic ash, and mash.
 class ImmersiveModeControllerAsh
     : public ImmersiveModeController,
       public ash::ImmersiveFullscreenControllerDelegate,
@@ -57,6 +59,13 @@ class ImmersiveModeControllerAsh
   // Returns true if the visibility of the tab indicators has changed.
   bool UpdateTabIndicators();
 
+  // Used when running in mash to create |mash_reveal_widget_|. Does nothing
+  // if already null.
+  void CreateMashRevealWidget();
+
+  // Destroys |mash_reveal_widget_| if valid, does nothing otherwise.
+  void DestroyMashRevealWidget();
+
   // ImmersiveFullscreenController::Delegate overrides:
   void OnImmersiveRevealStarted() override;
   void OnImmersiveRevealEnded() override;
@@ -97,6 +106,10 @@ class ImmersiveModeControllerAsh
   // |use_tab_indicators_|.
   double visible_fraction_;
 
+  // When running in mash a widget is created to draw the top container. This
+  // widget does not actually contain the top container, it just renders it.
+  std::unique_ptr<views::Widget> mash_reveal_widget_;
+
   content::NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(ImmersiveModeControllerAsh);