Update _computeMessageContent to use optional properties

Change-Id: I3c62dd39dfe2070cedf909f68c7dcaff9b8c99c1
diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message.ts b/polygerrit-ui/app/elements/change/gr-message/gr-message.ts
index f9a3baa..a25ff20 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message.ts
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message.ts
@@ -236,7 +236,7 @@
   }
 
   _computeMessageContentExpanded(content?: string, tag?: ReviewInputTag) {
-    return this._computeMessageContent(content, tag, true);
+    return this._computeMessageContent(true, content, tag);
   }
 
   _patchsetCommentSummary(commentThreads: CommentThread[] = []) {
@@ -268,7 +268,7 @@
     tag?: ReviewInputTag,
     commentThreads?: CommentThread[]
   ) {
-    const summary = this._computeMessageContent(content, tag, false);
+    const summary = this._computeMessageContent(false, content, tag);
     if (summary || !commentThreads) return summary;
     return this._patchsetCommentSummary(commentThreads);
   }
@@ -293,10 +293,11 @@
   }
 
   _computeMessageContent(
-    content = '',
-    tag: ReviewInputTag = '' as ReviewInputTag,
-    isExpanded: boolean
+    isExpanded: boolean,
+    content?: string,
+    tag?: ReviewInputTag
   ) {
+    if (!content) return '';
     const isNewPatchSet = this._isNewPatchsetTag(tag);
 
     const lines = content.split('\n');
diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message_test.js b/polygerrit-ui/app/elements/change/gr-message/gr-message_test.js
index 8ed49e0..94507e6 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message_test.js
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message_test.js
@@ -270,18 +270,18 @@
 
     suite('compute messages', () => {
       test('empty', () => {
-        assert.equal(element._computeMessageContent('', '', true), '');
-        assert.equal(element._computeMessageContent('', '', false), '');
+        assert.equal(element._computeMessageContent(true, '', ''), '');
+        assert.equal(element._computeMessageContent(false, '', ''), '');
       });
 
       test('new patchset', () => {
         const original = 'Uploaded patch set 1.';
         const tag = 'autogenerated:gerrit:newPatchSet';
-        let actual = element._computeMessageContent(original, tag, true);
+        let actual = element._computeMessageContent(true, original, tag);
         assert.equal(actual, element._computeMessageContentCollapsed(
             original, tag, []));
         assert.equal(actual, original);
-        actual = element._computeMessageContent(original, tag, false);
+        actual = element._computeMessageContent(false, original, tag);
         assert.equal(actual, original);
       });
 
@@ -289,11 +289,11 @@
         const original = 'Patch Set 27: Patch Set 26 was rebased';
         const tag = 'autogenerated:gerrit:newPatchSet';
         const expected = 'Patch Set 26 was rebased';
-        let actual = element._computeMessageContent(original, tag, true);
+        let actual = element._computeMessageContent(true, original, tag);
         assert.equal(actual, expected);
         assert.equal(actual, element._computeMessageContentCollapsed(
             original, tag, []));
-        actual = element._computeMessageContent(original, tag, false);
+        actual = element._computeMessageContent(false, original, tag);
         assert.equal(actual, expected);
       });
 
@@ -301,11 +301,11 @@
         const original = 'Patch Set 1:\n\nThis change is ready for review.';
         const tag = undefined;
         const expected = 'This change is ready for review.';
-        let actual = element._computeMessageContent(original, tag, true);
+        let actual = element._computeMessageContent(true, original, tag);
         assert.equal(actual, expected);
         assert.equal(actual, element._computeMessageContentCollapsed(
             original, tag, []));
-        actual = element._computeMessageContent(original, tag, false);
+        actual = element._computeMessageContent(false, original, tag);
         assert.equal(actual, expected);
       });
 
@@ -313,9 +313,9 @@
         const original = 'Patch Set 1: Code-Style+1';
         const tag = undefined;
         const expected = '';
-        let actual = element._computeMessageContent(original, tag, true);
+        let actual = element._computeMessageContent(true, original, tag);
         assert.equal(actual, expected);
-        actual = element._computeMessageContent(original, tag, false);
+        actual = element._computeMessageContent(false, original, tag);
         assert.equal(actual, expected);
       });
 
@@ -323,9 +323,9 @@
         const original = 'Patch Set 1:\n\n(3 comments)';
         const tag = undefined;
         const expected = '';
-        let actual = element._computeMessageContent(original, tag, true);
+        let actual = element._computeMessageContent(true, original, tag);
         assert.equal(actual, expected);
-        actual = element._computeMessageContent(original, tag, false);
+        actual = element._computeMessageContent(false, original, tag);
         assert.equal(actual, expected);
       });
     });
@@ -473,7 +473,7 @@
       }];
       assert.equal(element._computeMessageContentCollapsed(
           '', undefined, threads), 'testing the load');
-      assert.equal(element._computeMessageContent('', undefined, false), '');
+      assert.equal(element._computeMessageContent(false, '', undefined), '');
     });
 
     test('single patchset comment with reply', () => {
@@ -504,7 +504,7 @@
       }];
       assert.equal(element._computeMessageContentCollapsed(
           '', undefined, threads), 'n');
-      assert.equal(element._computeMessageContent('', undefined, false), '');
+      assert.equal(element._computeMessageContent(false, '', undefined), '');
     });
   });