Handle and send isRecipientUpdate sync messages

* Handle and send isRecipientUpdate sync messages
* Disable sending isRecipientUpdates for now

libtextsecure/sendmessage.js

@@ -23,7 +23,6 @@ function Message(options) {
   this.flags = options.flags;
   this.recipients = options.recipients;
   this.timestamp = options.timestamp;
-  this.needsSync = options.needsSync;
   this.expireTimer = options.expireTimer;
   this.profileKey = options.profileKey;
 
@@ -438,6 +437,7 @@ MessageSender.prototype = {
     expirationStartTimestamp,
     sentTo = [],
     unidentifiedDeliveries = [],
+    isUpdate = false,
     options
   ) {
     const myNumber = textsecure.storage.user.getNumber();
@@ -468,6 +468,10 @@ MessageSender.prototype = {
       Object.create(null)
     );
 
+    if (isUpdate) {
+      syncMessage.isRecipientUpdate = true;
+    }
+
     // Though this field has 'unidenified' in the name, it should have entries for each
     //   number we sent to.
     if (sentTo && sentTo.length) {
@@ -841,7 +845,6 @@ MessageSender.prototype = {
         attachments,
         quote,
         preview,
-        needsSync: true,
         expireTimer,
         profileKey,
       },
@@ -939,7 +942,6 @@ MessageSender.prototype = {
       attachments,
       quote,
       preview,
-      needsSync: true,
       expireTimer,
       profileKey,
       group: {
@@ -1054,7 +1056,6 @@ MessageSender.prototype = {
     const attrs = {
       recipients: numbers,
       timestamp,
-      needsSync: true,
       expireTimer,
       profileKey,
       flags: textsecure.protobuf.DataMessage.Flags.EXPIRATION_TIMER_UPDATE,
@@ -1087,7 +1088,6 @@ MessageSender.prototype = {
       {
         recipients: [number],
         timestamp,
-        needsSync: true,
         expireTimer,
         profileKey,
         flags: textsecure.protobuf.DataMessage.Flags.EXPIRATION_TIMER_UPDATE,