Introduce background Download process to android

chrome/android/java/AndroidManifest.xml

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Copyright 2015 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. -->
 
 <!--
 Note: This is a jinja2 template, processed at build time into the final manifest.
 
 Blocks denoted with { % block some_name % }foo{ % endblock % } can be overridden
 by a child template that "extends" this file.
@@ skipping 631 matching lines @@
         <!-- TODO(tedchoc): Omit this for release builds as MultiDex is debug only. --> 
         <meta-data android:name="{{ manifest_package }}{{ privileged_process_name }}.ignore_multidex"
 android:value="true" />
         <service android:name="org.chromium.content.app.PrivilegedProcessService{{ i }}"
             android:process="{{ privileged_process_name }}"
             android:permission="{{ manifest_package }}.permission.CHILD_SERVICE"
             android:isolatedProcess="false"
             android:exported="false" />
         {% endfor %}
 
+        <!-- Background download process, it may outlive chrome if download does not finish
+             when user kills chrome. Once created, the process will manage its own lifecycle.
+             To work around an issue in earlier android versions that a bound service will
+             get killed when chrome goes away, this service will only communicate with the
+             browser process through callbacks. -->
+        <service android:name="org.chromium.content.app.DownloadProcessService"
+            android:process=":download"
+            android:permission="{{ manifest_package }}.permission.CHILD_SERVICE"
+            android:isolatedProcess="false"
+            android:exported="false"/>
+
         <receiver android:name="org.chromium.chrome.browser.download.DownloadBroadcastReceiver"
             android:exported="false">
             <intent-filter>
                 <action android:name="android.intent.action.DOWNLOAD_NOTIFICATION_CLICKED"/>
             </intent-filter>
         </receiver>
 
         <receiver android:name="org.chromium.base.PowerStatusReceiver">
             <intent-filter>
                 <action android:name="android.intent.action.ACTION_POWER_CONNECTED"/>
@@ skipping 51 matching lines @@
              choose the first MediaRouteController that can play it, so the order of the list can be important.
              The most specific MediaRouteControllers should be listed first, followed by more generic ones.
              The downstream manifest replaces this block, and hence replaces the list of media route
              controllers with its own list. -->
         <meta-data android:name="org.chromium.content.browser.REMOTE_MEDIA_PLAYERS"
             android:value="org.chromium.chrome.browser.media.remote.DefaultMediaRouteController"/>
 
         {% endblock %}
     </application>
 </manifest>