Add WebView documentation about the layout height parameter.

 * and {@link WebChromeClient#onHideCustomView()} are required,

 * {@link WebChromeClient#getVideoLoadingProgressView()} is optional.

 * </p>

 *

 * <h3>Layout size</h3>

 * <p>

 * It is recommended to set the WebView layout height to a fixed value or to

 * {@link android.view.ViewGroup.LayoutParams#MATCH_PARENT} instead of using

 * {@link android.view.ViewGroup.LayoutParams#WRAP_CONTENT}.

 * When using {@link android.view.ViewGroup.LayoutParams#MATCH_PARENT}

 * for the height none of the WebView's parents should use a

 * {@link android.view.ViewGroup.LayoutParams#WRAP_CONTENT} layout height since that could result in

 * incorrect sizing of the views.

 * </p>

 *

 * <p>Setting the WebView's height to {@link android.view.ViewGroup.LayoutParams#WRAP_CONTENT}

 * enables the following behaviors:

 * <ul>

 * <li>The HTML body layout height is set to a fixed value. This means that elements with a height

 * relative to the HTML body may not be sized correctly. </li>

 * <li>For applications targetting {@link android.os.Build.VERSION_CODES#KITKAT} and earlier SDKs the

 * HTML viewport meta tag will be ignored in order to preserve backwards compatibility. </li>

 * </ul>

 * </p>

 *

 * <p>

 * Using a layout width of {@link android.view.ViewGroup.LayoutParams#WRAP_CONTENT} is not

 * supported. If such a width is used the WebView will attempt to use the width of the parent

 * instead.

 * </p>

 *

 */

// Implementation notes.

// The WebView is a thin API class that delegates its public API to a backend WebViewProvider