Bug 1624675 - Remove unused UIAsyncTask. r=snorp

Differential Revision: https://phabricator.services.mozilla.com/D68435

--HG--
extra : moz-landing-system : lando

mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/UIAsyncTask.java

@@ -1,121 +0,0 @@
-/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-package org.mozilla.gecko.util;
-
-import android.os.Handler;
-import android.os.Looper;
-
-/**
- * Executes a background task and publishes the result on the UI thread.
- *
- * The standard {@link android.os.AsyncTask} only runs onPostExecute on the
- * thread it is constructed on, so this is a convenience class for creating
- * tasks off the UI thread.
- *
- * We use generics differently to Android's AsyncTask.
- * Android uses a "Params" type parameter to represent the type of all the parameters to this task.
- * It then uses arguments of type Params... to permit arbitrarily-many of these to be passed
- * fluently.
- *
- * Unfortunately, since Java does not support generic array types (and since varargs desugars to a
- * single array parameter) that behaviour exposes a hole in the type system. See:
- * http://docs.oracle.com/javase/tutorial/java/generics/nonReifiableVarargsType.html#vulnerabilities
- *
- * Instead, we equivalently have a single type parameter "Param". A UiAsyncTask may take exactly one
- * parameter of type Param. Since Param can be an array type, this no more restrictive than the
- * other approach, it just provides additional type safety.
- */
-public abstract class UIAsyncTask<Param, Result> {
-    /**
-     * Provide a convenient API for parameter-free UiAsyncTasks by wrapping parameter-taking methods
-     * from UiAsyncTask in parameterless equivalents.
-     */
-    public static abstract class WithoutParams<InnerResult> extends UIAsyncTask<Void, InnerResult> {
-        public WithoutParams(final Handler backgroundThreadHandler) {
-            super(backgroundThreadHandler);
-        }
-
-        public void execute() {
-            execute(null);
-        }
-
-        @Override
-        protected InnerResult doInBackground(final Void unused) {
-            return doInBackground();
-        }
-
-        protected abstract InnerResult doInBackground();
-    }
-
-    final Handler mBackgroundThreadHandler;
-    private volatile boolean mCancelled;
-    private static Handler sHandler;
-
-    /**
-     * Creates a new asynchronous task.
-     *
-     * @param backgroundThreadHandler the handler to execute the background task on
-     */
-    public UIAsyncTask(final Handler backgroundThreadHandler) {
-        mBackgroundThreadHandler = backgroundThreadHandler;
-    }
-
-    private static synchronized Handler getUiHandler() {
-        if (sHandler == null) {
-            sHandler = new Handler(Looper.getMainLooper());
-        }
-
-        return sHandler;
-    }
-
-    private final class BackgroundTaskRunnable implements Runnable {
-        private final Param mParam;
-
-        public BackgroundTaskRunnable(final Param param) {
-            mParam = param;
-        }
-
-        @Override
-        public void run() {
-            final Result result = doInBackground(mParam);
-
-            getUiHandler().post(new Runnable() {
-                @Override
-                public void run() {
-                    if (mCancelled) {
-                        onCancelled();
-                    } else {
-                        onPostExecute(result);
-                    }
-                }
-            });
-        }
-    }
-
-    protected void execute(final Param param) {
-        getUiHandler().post(new Runnable() {
-            @Override
-            public void run() {
-                onPreExecute();
-                mBackgroundThreadHandler.post(new BackgroundTaskRunnable(param));
-            }
-        });
-    }
-
-    public final boolean cancel() {
-        mCancelled = true;
-        return mCancelled;
-    }
-
-    public final boolean isCancelled() {
-        return mCancelled;
-    }
-
-    protected void onPreExecute() { }
-    protected void onPostExecute(final Result result) { }
-    protected void onCancelled() { }
-    protected abstract Result doInBackground(Param param);
-}