Fix issue where search results could flicker.

Shoutout to @clauz9 for the help in researching this bug!

app/src/main/java/org/thoughtcrime/securesms/conversationlist/ConversationListItem.java

@@ -71,7 +71,6 @@ import org.thoughtcrime.securesms.recipients.RecipientForeverObserver;
 import org.thoughtcrime.securesms.recipients.RecipientId;
 import org.thoughtcrime.securesms.search.MessageResult;
 import org.thoughtcrime.securesms.util.DateUtils;
-import org.thoughtcrime.securesms.util.Debouncer;
 import org.thoughtcrime.securesms.util.ExpirationUtil;
 import org.thoughtcrime.securesms.util.MediaUtil;
 import org.thoughtcrime.securesms.util.SearchUtil;
@@ -122,8 +121,6 @@ public final class ConversationListItem extends ConstraintLayout
   private int             unreadCount;
   private AvatarImageView contactPhotoImage;
 
-  private final Debouncer subjectViewClearDebouncer = new Debouncer(150);
-
   private LiveData<SpannableString> displayBody;
 
   public ConversationListItem(Context context) {
@@ -175,7 +172,6 @@ public final class ConversationListItem extends ConstraintLayout
   {
     observeRecipient(thread.getRecipient().live());
     observeDisplayBody(null);
-    setSubjectViewText(null);
 
     this.threadId           = thread.getThreadId();
     this.glideRequests      = glideRequests;
@@ -188,7 +184,7 @@ public final class ConversationListItem extends ConstraintLayout
     if (highlightSubstring != null) {
       String name = recipient.get().isSelf() ? getContext().getString(R.string.note_to_self) : recipient.get().getDisplayName(getContext());
 
-      this.fromView.setText(recipient.get(), SearchUtil.getHighlightedSpan(locale, SpanUtil::getMediumBoldSpan, name, highlightSubstring, SearchUtil.MATCH_ALL), false, null);
+      this.fromView.setText(recipient.get(), SearchUtil.getHighlightedSpan(locale, SpanUtil::getMediumBoldSpan, name, highlightSubstring, SearchUtil.MATCH_ALL), true, null);
     } else {
       this.fromView.setText(recipient.get(), false);
     }
@@ -196,7 +192,9 @@ public final class ConversationListItem extends ConstraintLayout
     this.typingThreads = typingThreads;
     updateTypingIndicator(typingThreads);
 
-    observeDisplayBody(getThreadDisplayBody(getContext(), thread, glideRequests, thumbSize, thumbTarget));
+    LiveData<SpannableString> displayBody = getThreadDisplayBody(getContext(), thread, glideRequests, thumbSize, thumbTarget);
+    setSubjectViewText(displayBody.getValue());
+    observeDisplayBody(displayBody);
 
     if (thread.getDate() > 0) {
       CharSequence date = DateUtils.getBriefRelativeTimeSpanString(getContext(), locale, thread.getDate());
@@ -382,9 +380,8 @@ public final class ConversationListItem extends ConstraintLayout
 
   private void setSubjectViewText(@Nullable CharSequence text) {
     if (text == null) {
-      subjectViewClearDebouncer.publish(() -> subjectView.setText(null));
+      subjectView.setText(null);
     } else {
-      subjectViewClearDebouncer.clear();
       subjectView.setText(text);
       subjectView.setVisibility(VISIBLE);
     }
@@ -535,11 +532,11 @@ public final class ConversationListItem extends ConstraintLayout
         return emphasisAdded(context, context.getString(thread.isOutgoing() ? R.string.ThreadRecord_you_deleted_this_message : R.string.ThreadRecord_this_message_was_deleted), defaultTint);
       } else {
         String                    body      = removeNewlines(thread.getBody());
-        LiveData<SpannableString> finalBody = LiveDataUtil.mapAsync(createFinalBodyWithMediaIcon(context, body, thread, glideRequests, thumbSize, thumbTarget), updatedBody -> {
+        LiveData<SpannableString> finalBody = Transformations.map(createFinalBodyWithMediaIcon(context, body, thread, glideRequests, thumbSize, thumbTarget), updatedBody -> {
           if (thread.getRecipient().isGroup()) {
             RecipientId groupMessageSender = thread.getGroupMessageSender();
             if (!groupMessageSender.isUnknown()) {
-              return createGroupMessageUpdateString(context, updatedBody, Recipient.resolved(groupMessageSender), thread.isRead());
+              return createGroupMessageUpdateString(context, updatedBody, Recipient.resolved(groupMessageSender));
             }
           }
 
@@ -605,8 +602,7 @@ public final class ConversationListItem extends ConstraintLayout
 
   private static SpannableString createGroupMessageUpdateString(@NonNull Context context,
                                                                 @NonNull CharSequence body,
-                                                                @NonNull Recipient recipient,
+                                                                @NonNull Recipient recipient)
-                                                                boolean read)
   {
     String sender = (recipient.isSelf() ? context.getString(R.string.MessageRecord_you)
                                         : recipient.getShortDisplayName(context)) + ": ";

app/src/main/java/org/thoughtcrime/securesms/conversationlist/ConversationListSearchAdapter.java

@@ -107,7 +107,7 @@ class ConversationListSearchAdapter extends    RecyclerView.Adapter<Conversation
 
   void updateResults(@NonNull SearchResult result) {
     this.searchResult = result;
-    notifyDataSetChanged();
+    notifyItemRangeChanged(0, getItemCount());
   }
 
   @Nullable