SensitivePhoneNumbers: Load numbers only at first actual call to method

* Constructor is called during boot, adding boot time where
  it's not necessary
* Use the first actual call to a function to parse the list

Change-Id: I02548d004c5d78db65c872247cd36a0405d826ea

sdk/src/java/org/lineageos/internal/phone/SensitivePhoneNumbers.java

@@ -51,12 +51,11 @@ public class SensitivePhoneNumbers {
     private static final String ns = null;
 
     private static SensitivePhoneNumbers sInstance = null;
+    private static boolean sNumbersLoaded;
 
     private HashMap<String, ArrayList<String>> mSensitiveNumbersMap = new HashMap<>();
 
-    private SensitivePhoneNumbers() {
-        loadSensiblePhoneNumbers();
-    }
+    private SensitivePhoneNumbers() { }
 
     public static SensitivePhoneNumbers getInstance() {
         if (sInstance == null) {
@@ -66,6 +65,10 @@ public class SensitivePhoneNumbers {
     }
 
     private void loadSensiblePhoneNumbers() {
+        if (sNumbersLoaded) {
+            return;
+        }
+
         FileReader sensiblePNReader;
 
         File sensiblePNFile = new File(Environment.getRootDirectory(),
@@ -89,6 +92,8 @@ public class SensitivePhoneNumbers {
         } catch (IOException | XmlPullParserException e) {
             Log.w(LOG_TAG, "Exception in spn-conf parser", e);
         }
+
+        sNumbersLoaded = true;
     }
 
     private void readSensitivePNS(XmlPullParser parser)
@@ -113,6 +118,7 @@ public class SensitivePhoneNumbers {
     }
 
     public boolean isSensitiveNumber(Context context, String numberToCheck, int subId) {
+        loadSensiblePhoneNumbers();
         String nationalNumber = formatNumberToNational(context, numberToCheck);
 
         SubscriptionManager subManager = context.getSystemService(SubscriptionManager.class);