Decoupling visibility states from webcontent, adding visibility management in ResourceManager

athena/wm/public/window_manager_observer.h

Index: athena/wm/public/window_manager_observer.h
diff --git a/athena/wm/public/window_manager_observer.h b/athena/wm/public/window_manager_observer.h
index 49ef7536c50aa3bc487ff77fcbd4b762debb1e1d..9fb77ac95f6daae60457d3065470e839c385ed21 100644
--- a/athena/wm/public/window_manager_observer.h
+++ b/athena/wm/public/window_manager_observer.h
@@ -19,8 +19,11 @@ class ATHENA_EXPORT WindowManagerObserver {
   // Called immediately after going out of the overview mode.
   virtual void OnOverviewModeExit() = 0;
 
-  // Called after the activity order has changed.
-  virtual void OnActivityOrderHasChanged() = 0;
+  // Called immediately before the split mode is activated.
+  virtual void OnSplitViewModeEnter() = 0;
+
+  // Called immediately after going out of the splitview mode.
+  virtual void OnSplitViewModeExit() = 0;
 };
 
 }  // namespace athena