title: Android WebView tag a can not start a intent with tel Uri
body: <p><strong>Click Common tag a contains 'tel:' Uri in HTML can not start a intent in Android.<br>
  Here is my Android code:</strong>  </p>
  
  <pre><code>WebSettings webSettings = mWebView.getSettings();
      webSettings.setCacheMode(WebSettings.LOAD_NO_CACHE); //no cache
      webSettings.setJavaScriptEnabled(true);
      mWebView.addJavascriptInterface(new WebAppInterface(this), "Android");
      //This method will only be invoked with GET request
      mWebView.setWebViewClient(new WebViewClient(){
          @Override
          public boolean shouldOverrideUrlLoading(WebView view, String url) {
              //Log.d("DEBUG-URL","url:"+url);
              if(url.startsWith(WebView.SCHEME_TEL)){
                  Intent intent = new Intent(Intent.ACTION_DIAL,
                          Uri.parse(url));
                  startActivity(intent);
                  return true;
              }
              view.loadUrl(url);
              return true;
          }
      });  
  </code></pre>
  
  <p><strong>When I click the url in WebView, net: ERR_UNKNOWN_URL_SCHEME throws.</strong> </p>