CockpitPanel: update XML handling

Latest MSFS uses sConfigFile as an XML string instead of a file as
before. Add a new getXML method to the WebSim class and use it to
load the cockpit XML panel data when sConfigFile is updated.

Signed-off-by: Octavian Purdila <tavi@cs.pub.ro>

src/html_ui/WebSim/CockpitPanel.js

@@ -41,7 +41,7 @@ class WebSimCockpitPanelData {
     }
 
     setConfigFile(filename) {
-        this.sConfigFile = filename;
+        this.sConfigFile = WebSim.getXML("VFS/" + filename);
     }
 
     addInstrument(url, name, x, y, z, w) {

src/html_ui/WebSim/Utils.js

@@ -19,4 +19,16 @@ class WebSim {
             xhr.send();
         });
     }
+    static getXML(xmlPath) {
+        let xhr = new XMLHttpRequest();
+
+        xhr.open("GET", xmlPath, false);
+        xhr.send();
+        if (xhr.status === 200) {
+            return xhr.responseText;
+        } else {
+            return "";
+        }
+    }
+
 }