Supprot V2 app: step1

athena/env/public/athena_env.h

Index: athena/env/public/athena_env.h
diff --git a/athena/env/public/athena_env.h b/athena/env/public/athena_env.h
index 703a87f1d175878dcef288da14fa5de764febaef..b3bc8aa7d4f556967d81df5e31458f6930939d3a 100644
--- a/athena/env/public/athena_env.h
+++ b/athena/env/public/athena_env.h
@@ -6,15 +6,16 @@
 #define ATHENA_ENV_PUBLIC_ATHENA_ENV_H_
 
 #include "athena/athena_export.h"
-
-namespace gfx {
-class Insets;
-}
+#include "base/callback_forward.h"
 
 namespace aura {
 class WindowTreeHost;
 }
 
+namespace gfx {
+class Insets;
+}
+
 namespace athena {
 
 // AthenaEnv creates/shuts down the environment necessary to
@@ -32,6 +33,13 @@ class ATHENA_EXPORT AthenaEnv {
 
   // Sets the insets for the primary displays's work area.
   virtual void SetDisplayWorkAreaInsets(const gfx::Insets& insets) = 0;
+
+  // Adds the callback called when the athena is about to exit.
+  virtual void AddTerminatingCallback(const base::Closure& closure) = 0;
+  virtual void RemoveTerminatingCallback(const base::Closure& closure) = 0;
+
+  // Called when the athena is about to exist.
+  virtual void OnTerminating() = 0;
 };
 
 }  // namespace athena