Update targetSdkVersion to 20.

chrome/android/shell/java/AndroidManifest.xml

 <?xml version="1.0" encoding="utf-8"?>
 
 <!-- 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.
  -->
 
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="org.chromium.chrome.shell">
 
-    <uses-sdk android:minSdkVersion="14" android:targetSdkVersion="19" />
+    <uses-sdk android:minSdkVersion="14" android:targetSdkVersion="20" />
     <permission android:name="org.chromium.chrome.shell.permission.SANDBOX"
             android:protectionLevel="signature" />
     <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
     <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
     <uses-permission android:name="android.permission.CAMERA" />
     <uses-permission android:name="android.permission.GET_ACCOUNTS"/>
     <uses-permission android:name="android.permission.INTERNET"/>
     <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS"/>
     <uses-permission android:name="android.permission.RECORD_AUDIO"/>
@@ skipping 208 matching lines @@
         <receiver android:name="org.chromium.chrome.shell.signin.AccountsChangedReceiver">
             <intent-filter>
                 <action android:name="android.accounts.LOGIN_ACCOUNTS_CHANGED" />
             </intent-filter>
         </receiver>
         <meta-data android:name="org.chromium.content.browser.SMART_CLIP_PROVIDER"
                    android:value="org.chromium.content.browser.SmartClipProvider" />
 
     </application>
 </manifest>