Remove unused fields from ProcessObserver.

These fields are unused and holder object references unnecessarily,
possibly hurting garbage-collection.

Bug: 274764512
Test: built and ran a local image on cuttlefish; no obvious issues.
Change-Id: Ia04271cd2e29faba003feb96d87a629910a8d574
diff --git a/services/core/java/com/android/server/am/ActivityManagerShellCommand.java b/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
index 1b83327..ac8d56b 100644
--- a/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
+++ b/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
@@ -396,7 +396,7 @@
                 case "get-bg-restriction-level":
                     return runGetBgRestrictionLevel(pw);
                 case "observe-foreground-process":
-                    return runGetCurrentForegroundProcess(pw, mInternal, mTaskInterface);
+                    return runGetCurrentForegroundProcess(pw, mInternal);
                 case "reset-dropbox-rate-limiter":
                     return runResetDropboxRateLimiter();
                 case "list-displays-for-starting-users":
@@ -3644,11 +3644,10 @@
         return -1;
     }
 
-    private int runGetCurrentForegroundProcess(PrintWriter pw,
-            IActivityManager iam, IActivityTaskManager iatm)
+    private int runGetCurrentForegroundProcess(PrintWriter pw, IActivityManager iam)
             throws RemoteException {
 
-        ProcessObserver observer = new ProcessObserver(pw, iam, iatm, mInternal);
+        ProcessObserver observer = new ProcessObserver(pw, iam);
         iam.registerProcessObserver(observer);
 
         final InputStream mInput = getRawInputStream();
@@ -3683,15 +3682,10 @@
 
         private PrintWriter mPw;
         private IActivityManager mIam;
-        private IActivityTaskManager mIatm;
-        private ActivityManagerService mInternal;
 
-        ProcessObserver(PrintWriter mPw, IActivityManager mIam,
-                IActivityTaskManager mIatm, ActivityManagerService ams) {
+        ProcessObserver(PrintWriter mPw, IActivityManager mIam) {
             this.mPw = mPw;
             this.mIam = mIam;
-            this.mIatm = mIatm;
-            this.mInternal = ams;
         }
 
         @Override