Avoid webview memory leaks

WebVIewMemoryLeaks.java

@Override
    protected void onDestroy() {
        if(mWebView !=null ){
            mWebView.loadDataWithBaseURL(null, "", "text/html",
                    "utf-8", null);
            ((ViewGroup)mWebView.getParent()).removeView(mWebView);
            mWebView.destroy();
            mWebView = null;
        }
        super.onDestroy();
}