Simplify ArcServiceManager by stop deriving it from ArcIntentHelperObserver

components/arc/intent_helper/arc_intent_helper_observer.h

Index: components/arc/intent_helper/arc_intent_helper_observer.h
diff --git a/components/arc/intent_helper/arc_intent_helper_observer.h b/components/arc/intent_helper/arc_intent_helper_observer.h
index d8cc87e7d65c95973ec0c53c029b2a0648af770a..b0352fe442ff3be7bd5d9f6ec885e0ca4c84071f 100644
--- a/components/arc/intent_helper/arc_intent_helper_observer.h
+++ b/components/arc/intent_helper/arc_intent_helper_observer.h
@@ -11,8 +11,6 @@ class ArcIntentHelperObserver {
  public:
   // Called when app's intent filter is updated.
   virtual void OnAppsUpdated() = 0;
-
- protected:
   virtual ~ArcIntentHelperObserver() = default;
 };