Issue 4399 - Add WebView inheritor with ad blocking

libadblockplus-android-webviewapp/build.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<project name="Adblock Plus Library" default="help">
+<project name="AdblockWebView App" default="help">
 
     <!-- The local.properties file is created and updated by the 'android' tool.
          It contains the path to the SDK. It should *NOT* be checked into
          Version Control Systems. -->
     <property file="local.properties" />
 
     <!-- The ant.properties file can be created by you. It is only edited by the
          'android' tool to add properties to it.
          This is the place to change some Ant specific build properties.
          Here are some properties you may want to change/update:
@@ skipping 19 matching lines @@
          tool, as well as ADT.
 
          This contains project specific properties such as project target, and library
          dependencies. Lower level build properties are stored in ant.properties
          (or in .classpath for Eclipse projects).
 
          This file is an integral part of the build system for your
          application and should be checked into Version Control Systems. -->
     <loadproperties srcFile="project.properties" />
 
-    <target name="jni" description="Compiles and builds NDK libraries.">
-        <exec executable="${ndk.dir}/ndk-build" failonerror="true" />
-    </target>
+    <fail
+        message="sdk.dir is missing. Make sure to generate specify it in local.properties or to inject it through an env var"
+        unless="sdk.dir"
+    />
 
-    <target name="-pre-build" depends="jni">
+    <target name="-check-env">
+        <checkenv />
     </target>
 
     <target name="-pre-clean">
-        <delete dir="${native.libs.absolute.dir}/armeabi" verbose="${verbose}" />
-        <delete dir="${native.libs.absolute.dir}/armeabi-v7a" verbose="${verbose}" />
-        <delete dir="${native.libs.absolute.dir}/x86" verbose="${verbose}" />
         <delete dir="obj/" verbose="${verbose}" />
     </target>
 
     <!-- Import the actual build file.
 
          To customize existing targets, there are two options:
          - Customize only one target:
              - copy/paste the target into this file, *before* the
                <import> task.
              - customize it to your needs.
          - Customize the whole content of build.xml
              - copy/paste the content of the rules files (minus the top node)
                into this file, replacing the <import> task.
              - customize to your needs.
 
          ***********************
          ****** IMPORTANT ******
          ***********************
          In all cases you must update the value of version-tag below to read 'custom' instead of an integer,
          in order to avoid having your file be overridden by tools such as "android update project"
     -->
     <!-- version-tag: custom -->
     <import file="${sdk.dir}/tools/ant/build.xml" />
 
 </project>