Make InputDeviceDescriptors map private in InputController.

We added a getter method in ag/20559693 so mInputDeviceDescriptors can stay private now.

Bug: 237537306
Test: atest InputControllerTest

Change-Id: I7c44db6e53cb45047e90d0db470a0a2153ad3cd6
diff --git a/services/companion/java/com/android/server/companion/virtual/InputController.java b/services/companion/java/com/android/server/companion/virtual/InputController.java
index 96c71e5..0cea3d0 100644
--- a/services/companion/java/com/android/server/companion/virtual/InputController.java
+++ b/services/companion/java/com/android/server/companion/virtual/InputController.java
@@ -78,9 +78,8 @@
     final Object mLock;
 
     /* Token -> file descriptor associations. */
-    @VisibleForTesting
     @GuardedBy("mLock")
-    final Map<IBinder, InputDeviceDescriptor> mInputDeviceDescriptors = new ArrayMap<>();
+    private final Map<IBinder, InputDeviceDescriptor> mInputDeviceDescriptors = new ArrayMap<>();
 
     private final Handler mHandler;
     private final NativeWrapper mNativeWrapper;