MediaRouter: make request id globally unique

A unique request id can be used to identify each request
and the client of the request.

Test: atest mediaroutertest
Change-Id: I3234eaf0c4d398a47d412bc13ce711165d87e2db
diff --git a/services/core/java/com/android/server/media/MediaRoute2Provider.java b/services/core/java/com/android/server/media/MediaRoute2Provider.java
index 510dcd5..a30dd98 100644
--- a/services/core/java/com/android/server/media/MediaRoute2Provider.java
+++ b/services/core/java/com/android/server/media/MediaRoute2Provider.java
@@ -43,7 +43,7 @@
     }
 
     public abstract void requestCreateSession(String packageName, String routeId,
-            String controlCategory, int requestId);
+            String controlCategory, long requestId);
     public abstract void releaseSession(int sessionId);
 
     public abstract void selectRoute(int sessionId, MediaRoute2Info route);
@@ -86,6 +86,6 @@
     public interface Callback {
         void onProviderStateChanged(@Nullable MediaRoute2Provider provider);
         void onSessionCreated(@NonNull MediaRoute2Provider provider,
-                @Nullable RouteSessionInfo sessionInfo, int requestId);
+                @Nullable RouteSessionInfo sessionInfo, long requestId);
     }
 }