Add role=button and label to checks chip

Change-Id: Ibc38682c9c432936431ac253b7e589542262905c

gr-checks/gr-checks-chip-view.js

diff --git a/gr-checks/gr-checks-chip-view.js b/gr-checks/gr-checks-chip-view.js
index f87eb64..3415844 100644
--- a/gr-checks/gr-checks-chip-view.js
+++ b/gr-checks/gr-checks-chip-view.js
@@ -114,7 +114,11 @@
     </style>
     <template is="dom-if" if="[[_hasChecks]]">
       Checks:
-      <span class$="[[_chipClasses]]">
+      <span
+        class$="[[_chipClasses]]"
+        role="button"
+        aria-label="Open checks tab"
+      >
         <gr-checks-status
           status="[[_status]]"
           downgrade-failure-to-warning="[[_downgradeFailureToWarning]]">