Remove unnecessary field from AppWindowToken.

    public AppWindowAnimator(final AppWindowToken atoken) {

        mAppToken = atoken;

        mService = atoken.service;

        mAnimator = atoken.mAnimator;

        mAnimator = mService.mAnimator;

    }

    public void setAnimation(Animation anim, int width, int height, boolean skipFirstFrame) {

import com.android.server.input.InputApplicationHandle;

import com.android.server.wm.WindowManagerService.H;

import android.annotation.NonNull;

import android.content.pm.ActivityInfo;

import android.os.Message;

import android.os.RemoteException;

    // All of the windows and child windows that are included in this

    // application token.  Note this list is NOT sorted!

    final WindowList allAppWindows = new WindowList();

    final AppWindowAnimator mAppAnimator;

    final WindowAnimator mAnimator;

    @NonNull final AppWindowAnimator mAppAnimator;

    final boolean voiceInteraction;

        appToken = _token;

        voiceInteraction = _voiceInteraction;

        mInputApplicationHandle = new InputApplicationHandle(this);

        mAnimator = service.mAnimator;

        mAppAnimator = new AppWindowAnimator(this);

    }