Scroll to top if data changes

The problem: 
When reusing core-doc-page for multiple docs, scroll position is preserved when docs change. It is a bad user experience, you end up looking at the middle of a freshly loaded doc.
The fix:
Scroll to top when user data changes.
Question:
Is there a way to do this without traversing core-header-panel's internal structure? Hate doing that...

elements/core-doc-page.html

@@ -207,6 +207,11 @@ <h3 id="{{data.name}}.methods">Methods</h3>
           if (elementToFocus) {
             elementToFocus.scrollIntoView();
           }
+          else {
+            var viewer = this.shadowRoot.querySelector('core-header-panel /deep/ #mainContainer');
+            viewer.scrollTop = 0;
+            viewer.scrollLeft = 0;
+          }
         });
       }