Add a constant for the legacy controller version

PiperOrigin-RevId: 451857459

libraries/session/src/main/java/androidx/media3/session/MediaLibraryServiceLegacyStub.java

@@ -317,7 +317,7 @@ import java.util.concurrent.atomic.AtomicReference;
   public ControllerInfo createControllerInfo(RemoteUserInfo remoteUserInfo) {
     return new ControllerInfo(
         remoteUserInfo,
-        /* controllerVersion= */ 0,
+        ControllerInfo.LEGACY_CONTROLLER_VERSION,
         getMediaSessionManager().isTrustedForMediaControl(remoteUserInfo),
         new BrowserLegacyCb(remoteUserInfo),
         /* connectionHints= */ Bundle.EMPTY);

libraries/session/src/main/java/androidx/media3/session/MediaSession.java

@@ -322,6 +322,9 @@ public class MediaSession {
   /** Information of a {@link MediaController} or a {@link MediaBrowser}. */
   public static final class ControllerInfo {
 
+    /** The {@linkplain #getControllerVersion() controller version} of legacy controllers. */
+    public static final int LEGACY_CONTROLLER_VERSION = 0;
+
     private final RemoteUserInfo remoteUserInfo;
     private final int controllerVersion;
     private final boolean isTrusted;
@@ -454,7 +457,7 @@ public class MediaSession {
               /* uid= */ RemoteUserInfo.UNKNOWN_UID);
       return new ControllerInfo(
           legacyRemoteUserInfo,
-          /* controllerVersion= */ 0,
+          ControllerInfo.LEGACY_CONTROLLER_VERSION,
           /* trusted= */ false,
           /* cb= */ null,
           /* connectionHints= */ Bundle.EMPTY);

libraries/session/src/main/java/androidx/media3/session/MediaSessionLegacyStub.java

@@ -709,7 +709,7 @@ import org.checkerframework.checker.initialization.qual.Initialized;
       controller =
           new ControllerInfo(
               remoteUserInfo,
-              /* controllerVersion= */ 0,
+              ControllerInfo.LEGACY_CONTROLLER_VERSION,
               sessionManager.isTrustedForMediaControl(remoteUserInfo),
               controllerCb,
               /* connectionHints= */ Bundle.EMPTY);

libraries/session/src/main/java/androidx/media3/session/MediaSessionServiceLegacyStub.java

@@ -95,7 +95,7 @@ import java.util.concurrent.atomic.AtomicReference;
   public ControllerInfo createControllerInfo(RemoteUserInfo info) {
     return new ControllerInfo(
         info,
-        /* controllerVersion= */ 0,
+        ControllerInfo.LEGACY_CONTROLLER_VERSION,
         manager.isTrustedForMediaControl(info),
         /* cb= */ null,
         /* connectionHints= */ Bundle.EMPTY);