Flag voice messages as such in protos.

// FREEBIE

Signal/src/ViewControllers/MessagesViewController.m

@@ -3165,8 +3165,9 @@ typedef enum : NSUInteger {
     NSString *filename = [NSLocalizedString(@"VOICE_MESSAGE_FILE_NAME", @"Filename for voice messages.")
         stringByAppendingPathExtension:@".m4a"];
 
-    SignalAttachment *attachment =
-        [SignalAttachment attachmentWithData:audioData dataUTI:(NSString *)kUTTypeMPEG4Audio filename:filename];
+    SignalAttachment *attachment = [SignalAttachment voiceMessageAttachmentWithData:audioData
+                                                                            dataUTI:(NSString *)kUTTypeMPEG4Audio
+                                                                           filename:filename];
     if (!attachment || [attachment hasError]) {
         DDLogWarn(@"%@ %s Invalid attachment: %@.",
             self.tag,

Signal/src/ViewControllers/SignalAttachment.swift

@@ -89,6 +89,8 @@ class SignalAttachment: NSObject {
     // possible.
     public var image: UIImage?
 
+    private(set) public var isVoiceMessage = false
+
     // MARK: Constants
 
     /**
@@ -632,6 +634,14 @@ class SignalAttachment: NSObject {
                              filename : filename)
     }
 
+    // MARK: Voice Messages
+
+    public class func voiceMessageAttachment(data: Data?, dataUTI: String, filename: String?) -> SignalAttachment {
+        let attachment = audioAttachment(data : data, dataUTI : dataUTI, filename: filename)
+        attachment.isVoiceMessage = true
+        return attachment
+    }
+
     // MARK: Attachments
 
     // Factory method for attachments of any kind.

Signal/src/util/ThreadUtil.m

@@ -59,8 +59,7 @@ NS_ASSUME_NONNULL_BEGIN
     TSOutgoingMessage *message =
         [[TSOutgoingMessage alloc] initWithTimestamp:[NSDate ows_millisecondTimeStamp]
                                             inThread:thread
-                                         messageBody:nil
-                                       attachmentIds:[NSMutableArray new]
+                                      isVoiceMessage:[attachment isVoiceMessage]
                                     expiresInSeconds:(configuration.isEnabled ? configuration.durationSeconds : 0)];
     [messageSender sendAttachmentData:attachment.data
         contentType:attachment.mimeType