Add delete sync capability

service/src/main/java/org/whispersystems/textsecuregcm/controllers/DeviceController.java

@@ -232,6 +232,8 @@ public class DeviceController {
 
     if (capabilities == null) {
       throw new WebApplicationException(Response.status(422, "Missing device capabilities").build());
+    } else if (isCapabilityDowngrade(account, capabilities)) {
+      throw new WebApplicationException(Response.status(409).build());
     }
 
     final String signalAgent;
@@ -387,6 +389,10 @@ public class DeviceController {
     return Optional.of(aci);
   }
 
+  private static boolean isCapabilityDowngrade(Account account, DeviceCapabilities capabilities) {
+    return account.isDeleteSyncSupported() && !capabilities.deleteSync();
+  }
+
   private static String getUsedTokenKey(final String token) {
     return "usedToken::" + token;
   }

service/src/main/java/org/whispersystems/textsecuregcm/controllers/ProfileController.java

@@ -447,7 +447,7 @@ public class ProfileController {
     return new BaseProfileResponse(account.getIdentityKey(IdentityType.ACI),
         account.getUnidentifiedAccessKey().map(UnidentifiedAccessChecksum::generateFor).orElse(null),
         account.isUnrestrictedUnidentifiedAccess(),
-        new UserCapabilities(),
+        UserCapabilities.createForAccount(account),
         profileBadgeConverter.convert(
             getAcceptableLanguagesForRequest(containerRequestContext),
             account.getBadges(),
@@ -459,7 +459,7 @@ public class ProfileController {
     return new BaseProfileResponse(account.getIdentityKey(IdentityType.PNI),
         null,
         false,
-        new UserCapabilities(),
+        UserCapabilities.createForAccount(account),
         Collections.emptyList(),
         new PniServiceIdentifier(account.getPhoneNumberIdentifier()));
   }