Update targetSdkVersion to 23.

android_webview/tools/WebViewShell/AndroidManifest.xml

 <!--
  * 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.
 -->
 
 <manifest
     xmlns:android="http://schemas.android.com/apk/res/android"
     package="org.chromium.webview_shell"
     android:versionCode="1"
     android:versionName="1.0" >
 
-    <uses-sdk android:minSdkVersion="19" android:targetSdkVersion="22" />
+    <uses-sdk android:minSdkVersion="19" android:targetSdkVersion="23" />
 
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
     <uses-permission android:name="android.permission.CAMERA"/>
     <uses-permission android:name="android.permission.RECORD_AUDIO"/>
     <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS"/>
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.RUN_INSTRUMENTATION" />
 
@@ skipping 59 matching lines @@
             android:exported="true">
         </activity>
 
         <uses-library android:name="android.test.runner" />
     </application>
 
     <instrumentation android:name="org.chromium.webview_shell.WebViewLayoutTestRunner"
         android:targetPackage="org.chromium.webview_shell"
         android:label="Tests for org.chromium.webview_shell" />
 </manifest>