Notify Files App when ARC++ app is installed/removed

components/arc/intent_helper/arc_intent_helper_bridge.h

Index: components/arc/intent_helper/arc_intent_helper_bridge.h
diff --git a/components/arc/intent_helper/arc_intent_helper_bridge.h b/components/arc/intent_helper/arc_intent_helper_bridge.h
index 7a4de35c15ce20044e444a0a78b472924b927e5c..1955228ccd59c6e7231ee9ce8efca7514f47e779 100644
--- a/components/arc/intent_helper/arc_intent_helper_bridge.h
+++ b/components/arc/intent_helper/arc_intent_helper_bridge.h
@@ -12,10 +12,12 @@
 #include "ash/link_handler_model_factory.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "base/observer_list.h"
 #include "base/threading/thread_checker.h"
 #include "components/arc/arc_service.h"
 #include "components/arc/common/intent_helper.mojom.h"
 #include "components/arc/instance_holder.h"
+#include "components/arc/intent_helper/arc_intent_helper_observer.h"
 #include "mojo/public/cpp/bindings/binding.h"
 
 namespace ash {
@@ -52,6 +54,9 @@ class ArcIntentHelperBridge
       const scoped_refptr<LocalActivityResolver>& activity_resolver);
   ~ArcIntentHelperBridge() override;
 
+  void AddObserver(ArcIntentHelperObserver* observer);
+  void RemoveObserver(ArcIntentHelperObserver* observer);
+
   // InstanceHolder<mojom::IntentHelperInstance>::Observer
   void OnInstanceReady() override;
   void OnInstanceClosed() override;
@@ -97,6 +102,8 @@ class ArcIntentHelperBridge
 
   base::ThreadChecker thread_checker_;
 
+  base::ObserverList<ArcIntentHelperObserver> observer_list_;
+
   DISALLOW_COPY_AND_ASSIGN(ArcIntentHelperBridge);
 };