diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
index ffabb37..60c8ec0 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
@@ -1107,9 +1107,9 @@
     },
 
     _computeRelatedChangesClass(collapsed, loading) {
-      // TODO(beckysiegel) figure out how to check for customstyle in Polymer2,
-      // since customStyle was removed.
-      if (!loading && !this.customStyle['--relation-chain-max-height']) {
+      // TODO update to polymer 2.x syntax
+      if (!loading &&
+          !this.getComputedStyleValue('--relation-chain-max-height')) {
         this._updateRelatedChangeMaxHeight();
       }
       return collapsed ? 'collapsed' : '';
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
index a455c18..1a97c5c 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
@@ -66,6 +66,12 @@
       });
     });
 
+    getCustomCssValue = cssParam => {
+      // TODO: Update to be compatible with 2.x when we upgrade from
+      // 1.x to 2.x.
+      return element.getComputedStyleValue(cssParam);
+    };
+
     suite('keyboard shortcuts', () => {
       test('S should toggle the CL star', () => {
         const starStub = sandbox.stub(element.$.changeStar, 'toggleStar');
@@ -1067,10 +1073,10 @@
         // 20 (adjusted height) - 8 (remainder) = 12 (max height to set).
 
         element._updateRelatedChangeMaxHeight();
-        assert.equal(element.customStyle['--relation-chain-max-height'],
+        assert.equal(getCustomCssValue('--relation-chain-max-height'),
             '12px');
-        assert.equal(element.customStyle['--related-change-btn-top-padding'],
-            undefined);
+        assert.equal(getCustomCssValue('--related-change-btn-top-padding'),
+            '');
       });
 
       test('_updateRelatedChangeMaxHeight with commit toggle', () => {
@@ -1083,9 +1089,9 @@
         // 50 (existing height)  - 2 (remainder) = 48 (max height to set).
 
         element._updateRelatedChangeMaxHeight();
-        assert.equal(element.customStyle['--relation-chain-max-height'],
+        assert.equal(getCustomCssValue('--relation-chain-max-height'),
             '48px');
-        assert.equal(element.customStyle['--related-change-btn-top-padding'],
+        assert.equal(getCustomCssValue('--related-change-btn-top-padding'),
             '2px');
       });
 
@@ -1100,7 +1106,7 @@
         // 400 (new height) % 12 (line height) = 4 (remainder).
         // 400 (new height) - 4 (remainder) = 396.
 
-        assert.equal(element.customStyle['--relation-chain-max-height'],
+        assert.equal(getCustomCssValue('--relation-chain-max-height'),
             '396px');
       });
 
@@ -1119,7 +1125,7 @@
         // 100 (new height) % 12 (line height) = 4 (remainder).
         // 100 (new height) - 4 (remainder) = 96.
         element._updateRelatedChangeMaxHeight();
-        assert.equal(element.customStyle['--relation-chain-max-height'],
+        assert.equal(getCustomCssValue('--relation-chain-max-height'),
             '96px');
       });
 
diff --git a/polygerrit-ui/app/elements/shared/gr-alert/gr-alert_test.html b/polygerrit-ui/app/elements/shared/gr-alert/gr-alert_test.html
index b8dcb8d..79960d4 100644
--- a/polygerrit-ui/app/elements/shared/gr-alert/gr-alert_test.html
+++ b/polygerrit-ui/app/elements/shared/gr-alert/gr-alert_test.html
@@ -41,8 +41,7 @@
       assert.isNull(element.parentNode);
       element.show();
       assert.equal(element.parentNode, document.body);
-      element.customStyle['--gr-alert-transition-duration'] = '0ms';
-      element.updateStyles();
+      element.updateStyles({'--gr-alert-transition-duration': '0ms'});
       element.hide();
       assert.isNull(element.parentNode);
     });