Don't allow "show 2 more" reviewers

Collapsing reviewers only starts to make sense when you collapse more
than 2 reviewers.

Change-Id: I3952e7b64da66616a8e5abfd7c9f03ca3289fdf7
(cherry picked from commit 2f555d54441524472b909ced44bc3899ece150fb)

polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.js

diff --git a/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.js b/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.js
index 86e76b4..d8df9d4 100644
--- a/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.js
+++ b/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.js
@@ -186,10 +186,10 @@
         return reviewer._account_id != owner._account_id;
       });
 
-      // If there is one more than the max reviewers, don't show the 'show
-      // more' button, because it takes up just as much space.
+      // If there is one or two more than the max reviewers, don't show the
+      // 'show more' button, because it takes up just as much space.
       if (this.maxReviewersDisplayed &&
-          this._reviewers.length > this.maxReviewersDisplayed + 1) {
+          this._reviewers.length > this.maxReviewersDisplayed + 2) {
         this._displayedReviewers =
           this._reviewers.slice(0, this.maxReviewersDisplayed);
       } else {

polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list_test.html

diff --git a/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list_test.html b/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list_test.html
index 80359e0..ae4934c 100644
--- a/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list_test.html
+++ b/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list_test.html
@@ -214,10 +214,10 @@
       assert.isTrue(element.$$('.hiddenReviewers').hidden);
     });
 
-    test('show all reviewers button with 7 reviewers', () => {
+    test('show all reviewers button with 8 reviewers', () => {
       const reviewers = [];
       element.maxReviewersDisplayed = 5;
-      for (let i = 0; i < 7; i++) {
+      for (let i = 0; i < 8; i++) {
         reviewers.push(
           {email: i+'reviewer@google.com', name: 'reviewer-' + i});
       }
@@ -231,9 +231,9 @@
           CC: reviewers,
         },
       };
-      assert.equal(element._hiddenReviewerCount, 2);
+      assert.equal(element._hiddenReviewerCount, 3);
       assert.equal(element._displayedReviewers.length, 5);
-      assert.equal(element._reviewers.length, 7);
+      assert.equal(element._reviewers.length, 8);
       assert.isFalse(element.$$('.hiddenReviewers').hidden);
     });