Fix typo

Change-Id: I8f2f3fa9b4f346f951ba99a805641162573a690a
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js
index 4d66fe1..f374fd2 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js
@@ -57,7 +57,7 @@
         type: Object,
         notify: true,
         value() { return {}; },
-        observer: '_changeViewStatehanged',
+        observer: '_changeViewStateChanged',
       },
 
       _patchRange: Object,
@@ -492,7 +492,7 @@
       });
     },
 
-    _changeViewStatehanged(changeViewState) {
+    _changeViewStateChanged(changeViewState) {
       if (changeViewState.diffMode === null) {
         // If screen size is small, always default to unified view.
         this.$.restAPI.getPreferences().then(prefs => {