Handle devices disallowing start of FcmFetchService.

Some devices are overzealous with battery management and disallow
starting services even when they're in response to a high-priority FCM
message (which should be allowed). So in these situations, we just
fall back to what we were doing before.

app/src/main/java/org/thoughtcrime/securesms/gcm/FcmFetchService.java

@@ -1,10 +1,12 @@
 package org.thoughtcrime.securesms.gcm;
 
 import android.app.Service;
+import android.content.Context;
 import android.content.Intent;
 import android.os.Build;
 import android.os.IBinder;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
 import com.google.firebase.messaging.RemoteMessage;
@@ -70,25 +72,29 @@ public void onDestroy() {
   }
 
   private void fetch() {
+    retrieveMessages(this);
+
+    if (activeCount.decrementAndGet() == 0) {
+      Log.e(TAG, "stopping");
+      stopSelf();
+    }
+  }
+
+  static void retrieveMessages(@NonNull Context context) {
     BackgroundMessageRetriever retriever = ApplicationDependencies.getBackgroundMessageRetriever();
-    boolean                    success   = retriever.retrieveMessages(this, new RestStrategy(), new RestStrategy());
+    boolean                    success   = retriever.retrieveMessages(context, new RestStrategy(), new RestStrategy());
 
     if (success) {
       Log.i(TAG, "Successfully retrieved messages.");
     } else {
       if (Build.VERSION.SDK_INT >= 26) {
         Log.w(TAG, "Failed to retrieve messages. Scheduling on the system JobScheduler (API " + Build.VERSION.SDK_INT + ").");
-        FcmJobService.schedule(this);
+        FcmJobService.schedule(context);
       } else {
         Log.w(TAG, "Failed to retrieve messages. Scheduling on JobManager (API " + Build.VERSION.SDK_INT + ").");
-        ApplicationDependencies.getJobManager().add(new PushNotificationReceiveJob(this));
+        ApplicationDependencies.getJobManager().add(new PushNotificationReceiveJob(context));
       }
     }
-
-    if (activeCount.decrementAndGet() == 0) {
-      Log.e(TAG, "stopping");
-      stopSelf();
-    }
   }
 }
 

app/src/main/java/org/thoughtcrime/securesms/gcm/FcmReceiveService.java

@@ -2,6 +2,7 @@
 
 import android.content.Context;
 import android.content.Intent;
+import android.os.Build;
 
 import androidx.annotation.NonNull;
 
@@ -10,7 +11,9 @@
 
 import org.thoughtcrime.securesms.dependencies.ApplicationDependencies;
 import org.thoughtcrime.securesms.jobs.FcmRefreshJob;
+import org.thoughtcrime.securesms.jobs.PushNotificationReceiveJob;
 import org.thoughtcrime.securesms.logging.Log;
+import org.thoughtcrime.securesms.messages.RestStrategy;
 import org.thoughtcrime.securesms.registration.PushChallengeRequest;
 import org.thoughtcrime.securesms.util.TextSecurePreferences;
 
@@ -43,7 +46,12 @@ public void onNewToken(String token) {
   }
 
   private static void handleReceivedNotification(Context context) {
-    context.startService(new Intent(context, FcmFetchService.class));
+    try {
+      context.startService(new Intent(context, FcmFetchService.class));
+    } catch (Exception e) {
+      Log.w(TAG, "Failed to start service. Falling back to legacy approach.");
+      FcmFetchService.retrieveMessages(context);
+    }
   }
 
   private static void handlePushChallenge(@NonNull String challenge) {