Fix template types in gr-comment-thread

Change-Id: If813a5071483958251983046b02cf7e43dd526cb
diff --git a/polygerrit-ui/app/BUILD b/polygerrit-ui/app/BUILD
index b5da5d5..3a647d4 100644
--- a/polygerrit-ui/app/BUILD
+++ b/polygerrit-ui/app/BUILD
@@ -129,7 +129,6 @@
     "elements/gr-app-element_html.ts",
     "elements/settings/gr-watched-projects-editor/gr-watched-projects-editor_html.ts",
     "elements/shared/gr-account-list/gr-account-list_html.ts",
-    "elements/shared/gr-comment-thread/gr-comment-thread_html.ts",
 ]
 
 sources_for_template_checking = glob(
diff --git a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts
index fe4a66a..68df9c1 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts
+++ b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts
@@ -349,7 +349,8 @@
     return GerritNav.getUrlForComment(changeNum, projectName, id);
   }
 
-  getHighlightRange() {
+  /** The parameter is for triggering re-computation only. */
+  getHighlightRange(_: unknown) {
     const comment = this.comments?.[0];
     if (!comment) return undefined;
     if (comment.range) return comment.range;
@@ -378,9 +379,9 @@
     comments: UIComment[],
     changeNum?: NumericChangeId,
     projectName?: RepoName
-  ) {
-    if (!changeNum) return;
-    if (!projectName) return;
+  ): string {
+    if (!changeNum) return '';
+    if (!projectName) return '';
     check(comments.length > 0, 'comment not found');
     return GerritNav.getUrlForComment(changeNum, projectName, comments[0].id!);
   }
@@ -426,7 +427,7 @@
     });
   }
 
-  _isPatchsetLevelComment(path: string) {
+  _isPatchsetLevelComment(path?: string) {
     return path === SpecialFilePath.PATCHSET_LEVEL_COMMENTS;
   }
 
@@ -435,7 +436,7 @@
     return this.showPortedComment && comment.id === this._orderedComments[0].id;
   }
 
-  _computeDisplayPath(path: string) {
+  _computeDisplayPath(path?: string) {
     const displayPath = computeDisplayPath(path);
     if (displayPath === SpecialFilePath.PATCHSET_LEVEL_COMMENTS) {
       return 'Patchset';
@@ -741,7 +742,8 @@
     return -1;
   }
 
-  _computeHostClass(unresolved?: boolean) {
+  /** 2nd parameter is for triggering re-computation only. */
+  _computeHostClass(unresolved?: boolean, _?: unknown) {
     if (this.isRobotComment) {
       return 'robotComment';
     }
diff --git a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_html.ts b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_html.ts
index 245f71c..4bd359c 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_html.ts
@@ -241,9 +241,7 @@
         </gr-diff>
         <div class="view-diff-container">
           <a href="[[_getUrlForViewDiff(comments, changeNum, projectName)]]">
-            <gr-button link class="view-diff-button" on-click="_handleViewDiff">
-              View Diff
-            </gr-button>
+            <gr-button link class="view-diff-button">View Diff</gr-button>
           </a>
         </div>
       </div>
diff --git a/polygerrit-ui/app/utils/path-list-util.ts b/polygerrit-ui/app/utils/path-list-util.ts
index fd922fc..411421e 100644
--- a/polygerrit-ui/app/utils/path-list-util.ts
+++ b/polygerrit-ui/app/utils/path-list-util.ts
@@ -95,13 +95,13 @@
   });
 }
 
-export function computeDisplayPath(path: string) {
+export function computeDisplayPath(path?: string) {
   if (path === SpecialFilePath.COMMIT_MESSAGE) {
     return 'Commit message';
   } else if (path === SpecialFilePath.MERGE_LIST) {
     return 'Merge list';
   }
-  return path;
+  return path ?? '';
 }
 
 export function isMagicPath(path?: string) {