Add minSdkVersion=21 to ABI split manifests

build/android/gyp/generate_split_manifest.py

 #!/usr/bin/env python
 #
 # 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.
 """Creates an AndroidManifest.xml for an APK split.
 
 Given the manifest file for the main APK, generates an AndroidManifest.xml with
 the value required for a Split APK (package, versionCode, etc).
 """
 
 import lxml.etree
 import optparse
 
 from util import build_utils
 
 MANIFEST_TEMPLATE = """<?xml version="1.0" encoding="utf-8"?>
 <manifest
     xmlns:android="http://schemas.android.com/apk/res/android"
     package="%(package)s"
     split="%(split)s">
+  <uses-sdk android:minSdkVersion="21" />
   <application android:hasCode="%(has_code)s">
   </application>
 </manifest>
 """
 
 def ParseArgs():
   """Parses command line options.
 
   Returns:
     An options object as from optparse.OptionsParser.parse_args()
@@ skipping 55 matching lines @@
     f.write(split_manifest)
 
   if options.depfile:
     build_utils.WriteDepfile(
         options.depfile,
         [main_manifest] + build_utils.GetPythonDependencies())
 
 
 if __name__ == '__main__':
   main()