Post startService() in onResume() as a possible fix to an Android P bug.

Got confirmation that the crash we're seeing is a bug, and this might be
a possible workaround.

src/org/thoughtcrime/securesms/PassphraseRequiredActionBarActivity.java

@@ -17,6 +17,7 @@ import org.thoughtcrime.securesms.push.SignalServiceNetworkAccess;
 import org.thoughtcrime.securesms.service.KeyCachingService;
 import org.thoughtcrime.securesms.service.MessageRetrievalService;
 import org.thoughtcrime.securesms.util.TextSecurePreferences;
+import org.thoughtcrime.securesms.util.Util;
 
 import java.util.Locale;
 
@@ -60,10 +61,14 @@ public abstract class PassphraseRequiredActionBarActivity extends BaseActionBarA
   protected void onResume() {
     Log.i(TAG, "onResume()");
     super.onResume();
+
+    // Android P has a bug in foreground timings where starting a service in onResume() can still crash
+    Util.postToMain(() -> {
       KeyCachingService.registerPassphraseActivityStarted(this);
 
       if (!networkAccess.isCensored(this)) MessageRetrievalService.registerActivityStarted(this);
       else                                 ApplicationContext.getInstance(this).getJobManager().add(new PushNotificationReceiveJob(this));
+    });
 
     isVisible = true;
   }

src/org/thoughtcrime/securesms/WebRtcCallActivity.java

@@ -48,6 +48,7 @@ import org.thoughtcrime.securesms.service.MessageRetrievalService;
 import org.thoughtcrime.securesms.service.WebRtcCallService;
 import org.thoughtcrime.securesms.util.ServiceUtil;
 import org.thoughtcrime.securesms.util.TextSecurePreferences;
+import org.thoughtcrime.securesms.util.Util;
 import org.thoughtcrime.securesms.util.ViewUtil;
 import org.whispersystems.libsignal.IdentityKey;
 import org.whispersystems.libsignal.SignalProtocolAddress;
@@ -88,7 +89,12 @@ public class WebRtcCallActivity extends Activity {
   public void onResume() {
     Log.i(TAG, "onResume()");
     super.onResume();
+
+    // Android P has a bug in foreground timings where starting a service in onResume() can still crash
+    Util.postToMain(() -> {
       if (!networkAccess.isCensored(this)) MessageRetrievalService.registerActivityStarted(this);
+    });
+
     initializeScreenshotSecurity();
     EventBus.getDefault().register(this);
   }

src/org/thoughtcrime/securesms/util/Util.java

@@ -384,6 +384,10 @@ public class Util {
     }
   }
 
+  public static void postToMain(final @NonNull Runnable runnable) {
+    handler.post(runnable);
+  }
+
   public static void runOnMain(final @NonNull Runnable runnable) {
     if (isMainThread()) runnable.run();
     else                handler.post(runnable);