Make VR screen tap tests more stable

chrome/test/data/android/webvr_instrumentation/html/test_screen_taps_registered_on_cardboard.html

Index: chrome/test/data/android/webvr_instrumentation/html/test_screen_taps_registered_on_cardboard.html
diff --git a/chrome/test/data/android/webvr_instrumentation/html/test_screen_taps_registered_on_cardboard.html b/chrome/test/data/android/webvr_instrumentation/html/test_screen_taps_registered_on_cardboard.html
index 6fe56a8212e3b9a021bd66ffe920ca1c6ff3578b..7abb84b64e663b7bf6bfba4986179bb61efdd209 100644
--- a/chrome/test/data/android/webvr_instrumentation/html/test_screen_taps_registered_on_cardboard.html
+++ b/chrome/test/data/android/webvr_instrumentation/html/test_screen_taps_registered_on_cardboard.html
@@ -17,7 +17,14 @@ Cardboard
       window.addEventListener("vrdisplaypresentchange",
           () => {finishJavascriptStep();}, false);
       var numTaps = 0;
-      webglCanvas.addEventListener("click", () => {numTaps++;}, false);
+      webglCanvas.addEventListener("click",
+          () => {
+            numTaps++;
+            // Notify Java when we've received the tap after entering VR
+            if (numTaps == 2) {
+              t.done();
+            }
+          }, false);
 
       function stepVerifyNoInitialTaps() {
         t.step( () => {
@@ -25,15 +32,6 @@ Cardboard
         });
         finishJavascriptStep();
       }
-
-      function stepVerifyAdditionalTap() {
-          t.step_func_done( () => {
-            // We expect 1 tap from entering VR + 1 additional one after
-            assert_equals(numTaps, 2,
-                "Two taps registered after two taps given");
-          })();
-      }
-
     </script>
   </body>
 </html>