Remove stale ChromiumAsyncUrlRequest.java as it is replaced by...

Remove stale ChromiumAsyncUrlRequest.java as it is replaced by CronetUrlRequest.java as of https://codereview.chromium.org/520093002/.

BUG=409926
TBR=mmenke@chromium.org

Review URL: https://codereview.chromium.org/569713003

Cr-Commit-Position: refs/heads/master@{#294911}

components/cronet/android/java/src/org/chromium/net/ChromiumAsyncUrlRequest.java

-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-package org.chromium.net;
-
-/**
- * Async request using the native HTTP stack implementation.
- */
-public class ChromiumAsyncUrlRequest implements AsyncUrlRequest {
-    @Override
-    public void setHttpMethod(String method) {
-
-    }
-
-    @Override
-    public void addHeader(String header, String value) {
-
-    }
-
-    @Override
-    public void start(AsyncUrlRequestListener listener) {
-
-    }
-
-    @Override
-    public void cancel() {
-
-    }
-
-    @Override
-    public boolean isCanceled() {
-        return false;
-    }
-
-    @Override
-    public void pause() {
-
-    }
-
-    @Override
-    public boolean isPaused() {
-        return false;
-    }
-
-    @Override
-    public void resume() {
-
-    }
-}