[Android Webview] Refactor LoadUrlTest and work on embedded_test_server custom handler

android_webview/embeddedtestserver/java/src/org/chromium/net/test/AwEmbeddedTestServerService.java

+// Copyright 2017 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.test;
+
+import android.app.Service;
+import android.content.Intent;
+import android.os.IBinder;
+
+/**
+ * A {@link android.app.Service} that creates a new {@link AwEmbeddedTestServer} when bound.
+ */
+public class AwEmbeddedTestServerService extends Service {
+    @Override
+    public IBinder onBind(Intent intent) {
+        return new AwEmbeddedTestServerImpl(this);
+    }
+}