WifiStateChangeService: use Intent static start method pattern

This is the standard pattern for starting IntentServices.  It also makes
it really easy to trace what is starting this Service.

app/src/main/java/org/fdroid/fdroid/FDroidApp.java

@@ -386,12 +386,12 @@ public class FDroidApp extends Application {
         ImageLoader.getInstance().init(config);
 
         FDroidApp.initWifiSettings();
-        startService(new Intent(this, WifiStateChangeService.class));
+        WifiStateChangeService.start(this, null);
         // if the HTTPS pref changes, then update all affected things
         Preferences.get().registerLocalRepoHttpsListeners(new ChangeListener() {
             @Override
             public void onPreferenceChange() {
-                startService(new Intent(FDroidApp.this, WifiStateChangeService.class));
+                WifiStateChangeService.start(getApplicationContext(), null);
             }
         });
 

app/src/main/java/org/fdroid/fdroid/localrepo/type/WifiSwap.java

@@ -2,23 +2,16 @@ package org.fdroid.fdroid.localrepo.type;
 
 import android.annotation.SuppressLint;
 import android.content.Context;
-import android.content.Intent;
 import android.os.Handler;
 import android.os.Looper;
 import android.os.Message;
 import android.util.Log;
-
 import org.fdroid.fdroid.FDroidApp;
 import org.fdroid.fdroid.Preferences;
 import org.fdroid.fdroid.Utils;
 import org.fdroid.fdroid.localrepo.SwapService;
 import org.fdroid.fdroid.net.LocalHTTPD;
 import org.fdroid.fdroid.net.WifiStateChangeService;
-
-import java.io.IOException;
-import java.net.BindException;
-import java.util.Random;
-
 import rx.Single;
 import rx.SingleSubscriber;
 import rx.android.schedulers.AndroidSchedulers;
@@ -26,6 +19,10 @@ import rx.functions.Action1;
 import rx.functions.Func2;
 import rx.schedulers.Schedulers;
 
+import java.io.IOException;
+import java.net.BindException;
+import java.util.Random;
+
 @SuppressWarnings("LineLength")
 public class WifiSwap extends SwapType {
 
@@ -143,7 +140,7 @@ public class WifiSwap extends SwapType {
                         } catch (BindException e) {
                             int prev = FDroidApp.port;
                             FDroidApp.port = FDroidApp.port + new Random().nextInt(1111);
-                            context.startService(new Intent(context, WifiStateChangeService.class));
+                            WifiStateChangeService.start(context, null);
                             singleSubscriber.onError(new Exception("port " + prev + " occupied, trying on " + FDroidApp.port + "!"));
                         } catch (IOException e) {
                             Log.e(TAG, "Could not start local repo HTTP server", e);

app/src/main/java/org/fdroid/fdroid/net/WifiStateChangeService.java

@@ -1,16 +1,17 @@
 package org.fdroid.fdroid.net;
 
 import android.app.IntentService;
+import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
 import android.net.DhcpInfo;
 import android.net.NetworkInfo;
 import android.net.wifi.WifiInfo;
 import android.net.wifi.WifiManager;
+import android.support.annotation.Nullable;
 import android.support.v4.content.LocalBroadcastManager;
 import android.text.TextUtils;
 import android.util.Log;
-
 import org.apache.commons.net.util.SubnetUtils;
 import org.fdroid.fdroid.FDroidApp;
 import org.fdroid.fdroid.Preferences;
@@ -34,7 +35,7 @@ import java.util.Locale;
  * which is how it can be triggered by code, or it came in from the system
  * via {@link  org.fdroid.fdroid.receiver.WifiStateChangeReceiver}, in
  * which case an instance of {@link NetworkInfo} is included.
- *
+ * <p>
  * The work is done in a {@link Thread} so that new incoming {@code Intents}
  * are not blocked by processing. A new {@code Intent} immediately nullifies
  * the current state because it means that something about the wifi has
@@ -54,6 +55,14 @@ public class WifiStateChangeService extends IntentService {
         super("WifiStateChangeService");
     }
 
+    public static void start(Context context, @Nullable Intent intent) {
+        if (intent == null) {
+            intent = new Intent(WifiManager.NETWORK_STATE_CHANGED_ACTION);
+        }
+        intent.setComponent(new ComponentName(context, WifiStateChangeService.class));
+        context.startService(intent);
+    }
+
     @Override
     protected void onHandleIntent(Intent intent) {
         android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_LOWEST);

app/src/main/java/org/fdroid/fdroid/receiver/WifiStateChangeReceiver.java

@@ -1,11 +1,9 @@
 package org.fdroid.fdroid.receiver;
 
 import android.content.BroadcastReceiver;
-import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
 import android.net.wifi.WifiManager;
-
 import org.fdroid.fdroid.Utils;
 import org.fdroid.fdroid.net.WifiStateChangeService;
 
@@ -15,8 +13,7 @@ public class WifiStateChangeReceiver extends BroadcastReceiver {
     @Override
     public void onReceive(Context context, Intent intent) {
         if (WifiManager.NETWORK_STATE_CHANGED_ACTION.equals(intent.getAction())) {
-            intent.setComponent(new ComponentName(context, WifiStateChangeService.class));
-            context.startService(intent);
+            WifiStateChangeService.start(context, intent);
         } else {
             Utils.debugLog(TAG, "received unsupported Intent: " + intent);
         }