arc: Stop/start ARC++ kiosk app when maintenance session started/finished.

components/arc/kiosk/arc_kiosk_bridge.h

Index: components/arc/kiosk/arc_kiosk_bridge.h
diff --git a/components/arc/kiosk/arc_kiosk_bridge.h b/components/arc/kiosk/arc_kiosk_bridge.h
index ab0323f971a9259c894a5d532093d9f0896a0a11..fa04fe9b27bc07accd16290ebb72144d64d9bda9 100644
--- a/components/arc/kiosk/arc_kiosk_bridge.h
+++ b/components/arc/kiosk/arc_kiosk_bridge.h
@@ -21,7 +21,16 @@ class ArcKioskBridge : public ArcService,
                        public InstanceHolder<mojom::KioskInstance>::Observer,
                        public mojom::KioskHost {
  public:
-  explicit ArcKioskBridge(ArcBridgeService* bridge_service);
+  // Received IPCs are passed to this delegate.
+  class Delegate {
+   public:
+    virtual ~Delegate() = default;
+    virtual void OnMaintenanceSessionCreated() = 0;
+    virtual void OnMaintenanceSessionFinished() = 0;
+  };
+
+  // |delegate| should be alive while the ArcKioskBridge instance is alive.
+  ArcKioskBridge(ArcBridgeService* bridge_service, Delegate* delegate);
   ~ArcKioskBridge() override;
 
   // InstanceHolder<mojom::KioskInstance>::Observer overrides.
@@ -33,6 +42,7 @@ class ArcKioskBridge : public ArcService,
 
  private:
   mojo::Binding<mojom::KioskHost> binding_;
+  Delegate* const delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcKioskBridge);
 };