docs: add note about javascript interface to 4.2 overview

android:minSdkVersion}</a> is lower than 17, your app is not able to modify the settings that have

moved to {@link android.provider.Settings.Global} when running on Android 4.2 and higher.</p>

  </li>

  <li>If your app uses {@link android.webkit.WebView}, Android 4.2 adds an additional layer of

  security so you can more safely <b>bind JavaScript to your

  Android code</b>. If you set your

  <a href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#target">{@code targetSdkVersion}</a>

  to 17 or higher, you must now add the {@code @JavascriptInterface} annotation to any method that you

  want available to your JavaScript (the method must also be public). If you do not provide the

  annotation, the method is not accessible by a web page in your {@link android.webkit.WebView}

  when running on Android 4.2 or higher. If you set the

  <a href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#target">{@code targetSdkVersion}</a>

  to 16 or lower, the annotation is not required, but we recommend that you update your target version

  and add the annotation for additional security.

    <p>Read more about <a href="{@docRoot}guide/webapps/webview.html#BindingJavaScript">binding

    JavaScript code to Android code</a>.</p></li>

</ul>

href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#target">{@code targetSdkVersion}</a>

to 17 or higher, <strong>you

must add the {@code &#64;JavascriptInterface} annotation</strong> to any method that you want

available your web page code (the method must also be public). If you do not provide the

annotation, then the method will not accessible by your web page when running on Android 4.2 or

available to your JavaScript (the method must also be public). If you do not provide the

annotation, the method is not accessible by your web page when running on Android 4.2 or

higher.</p>

<p>In this example, the {@code WebAppInterface} class allows the web page to create a {@link