polishing serial backend and background page

background.js

@@ -10,9 +10,9 @@ function start_app() {
         window_child.onClosed.addListener(function() {
             // connectionId is passed from the script side through the chrome.runtime.getBackgroundPage refference
             // allowing us to automatically close the port when application shut down
-            if (connectionId != -1) {
-                chrome.serial.close(connectionId, function() {
-                    console.log('CLEANUP: Connection to serial port was opened after application closed, closing the connection.');
+            if (app_window.connectionId > 0) {
+                chrome.serial.close(app_window.connectionId, function(result) {
+                    console.log('SERIAL: Connection closed - ' + result);
                 });
             }
         });

js/serial_backend.js

@@ -149,11 +149,10 @@ $(document).ready(function() {
     });     
 }); 
 
-function onOpen(openInfo) {
-    connectionId = openInfo.connectionId;
-    backgroundPage.connectionId = openInfo.connectionId; // also pass connectionId to the background page
-    
-    if (connectionId != -1) {
+function onOpen(openInfo) {    
+    if (openInfo.connectionId > 0) {
+        connectionId = openInfo.connectionId;
+        
         // update connected_to
         GUI.connected_to = GUI.connecting_to;
         
@@ -229,20 +228,17 @@ function onOpen(openInfo) {
 }
 
 function onClosed(result) {
-    if (result) { // All went as expected
-        connectionId = -1; // reset connection id
-        backgroundPage.connectionId = connectionId; // also pass latest connectionId to the background page
-        
+    connectionId = -1; // reset connection id
+
+    if (result) { // All went as expected        
         sensor_status(sensors_detected = 0); // reset active sensor indicators
         $('#tabs > ul li').removeClass('active'); // de-select any selected tabs
         tab_initialize_default();
         
         console.log('Connection closed successfully.');
     } else { // Something went wrong
-        if (connectionId > 0) {
-            console.log('There was an error that happened during "connection-close" procedure.');
-            notify('Failed to close serial port', 'red');
-        }
+        console.log('There was an error that happened during "connection-close" procedure.');
+        notify('Failed to close serial port', 'red');
     } 
 }
 

main.js

@@ -2,10 +2,9 @@
 // This object is used to pass current connectionId to the backround page
 // so the onClosed event can close the port for us if it was left opened, without this
 // users can experience weird behavior if they would like to access the serial bus afterwards.
-var backgroundPage;
 chrome.runtime.getBackgroundPage(function(result) {
     backgroundPage = result;
-    backgroundPage.connectionId = -1;
+    backgroundPage.app_window = window;
 });
 
 var timers = new Array();