Fix range issue with comment replies

- Adds range when parent exists when comment POSTed
- Finds range via filtering comments for backfill

Bug: Issue 5459
Change-Id: Ied19cc4b33749ba81fad6d1a5030abab419b1e6f

polygerrit-ui/app/elements/diff/gr-diff-comment-thread/gr-diff-comment-thread.js

@@ -83,7 +83,7 @@
             lastComment.id || lastComment.__draftID);
         commentEl.editing = true;
       } else {
-        this.addDraft(opt_lineNum);
+        this.addDraft(opt_lineNum, lastComment.range);
       }
     },
 
@@ -159,7 +159,8 @@
           this._orderedComments[this._orderedComments.length - 1].id,
           parent.line,
           content,
-          opt_unresolved);
+          opt_unresolved,
+          parent.range);
 
       // If there is currently a comment in an editing state, add an attribute
       // so that the gr-diff-comment knows not to populate the draft text.
@@ -223,9 +224,11 @@
       return null;
     },
 
-    _newReply: function(inReplyTo, opt_lineNum, opt_message, opt_unresolved) {
+    _newReply: function(inReplyTo, opt_lineNum, opt_message, opt_unresolved,
+          opt_range) {
       var d = this._newDraft(opt_lineNum);
       d.in_reply_to = inReplyTo;
+      d.range = opt_range;
       if (opt_message != null) {
         d.message = opt_message;
       }

polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js

@@ -728,6 +728,26 @@
           this._getDiffCommentsFetchURL(changeNum, endpoint, opt_patchNum);
       promises.push(this.fetchJSON(url).then(function(response) {
         comments = response[opt_path] || [];
+
+        // TODO(kaspern): Implement this on in the backend so this can be
+        // removed.
+
+        // Sort comments by date so that parent ranges can be propagated in a
+        // single pass.
+        comments = comments.sort(function(a, b) {
+          return a.updated > b.updated;
+        });
+        comments.forEach(function(comment){
+          if (comment.in_reply_to && !comment.range) {
+            for (var i = 0; i < comments.length; i++) {
+              if (comments[i].id === comment.in_reply_to) {
+                comment.range = comments[i].range;
+                break;
+              }
+            }
+          }
+        });
+
         if (opt_basePatchNum == PARENT_PATCH_NUM) {
           baseComments = comments.filter(onlyParent);
           baseComments.forEach(setPath);