Fix XR controller test race condition

Fixes a race condition in XR tests that use the test_gamepad_button.html
test page. It was possible for finishJavaScriptStep() to be called
multiple times before the Java/C++ code could ack the first one, leading
to test failures.

Bug: 990843
Change-Id: I6e1a92c9cc3512862fb6441a1bad5efecff3a83c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1736801
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Reviewed-by: Alexander Cooper <alcooper@chromium.org>
Cr-Commit-Position: refs/heads/master@{#684120}

chrome/android/javatests/src/org/chromium/chrome/browser/vr/WebXrVrInputTest.java

@@ -194,6 +194,9 @@ public class WebXrVrInputTest {
         // Send a controller click and wait for JavaScript to receive it.
         controller.sendClickButtonToggleEvent();
         mWebVrTestFramework.waitOnJavaScriptStep();
+        // Re-register the callback since it unregisters itself after finishing the step.
+        mWebVrTestFramework.runJavaScriptOrFail(
+                "onPresentingAnimationFrameCallback = gamepadFrameCallback", POLL_TIMEOUT_SHORT_MS);
         controller.sendClickButtonToggleEvent();
         mWebVrTestFramework.waitOnJavaScriptStep();
         mWebVrTestFramework.endTest();
@@ -380,6 +383,9 @@ public class WebXrVrInputTest {
                 TestVrShellDelegate.getVrShellForTesting().getPresentationViewForTesting();
         long downTime = sendScreenTouchDown(presentationView, x, y);
         mWebVrTestFramework.waitOnJavaScriptStep();
+        // Re-register the callback since it unregisters itself after finishing the step.
+        mWebVrTestFramework.runJavaScriptOrFail(
+                "onPresentingAnimationFrameCallback = gamepadFrameCallback", POLL_TIMEOUT_SHORT_MS);
         sendScreenTouchUp(presentationView, x, y, downTime);
         mWebVrTestFramework.waitOnJavaScriptStep();
         mWebVrTestFramework.endTest();

chrome/browser/vr/webxr_vr_input_browser_test.cc

@@ -771,6 +771,10 @@ IN_PROC_BROWSER_TEST_F(WebVrOpenVrBrowserTest, TestControllerInputRegistered) {
   // Press and release the trigger, ensuring the Gamepad API detects both.
   my_mock.TogglePrimaryTrigger(controller_index);
   WaitOnJavaScriptStep();
+  // Re-register the callback since it unregisters itself after finishing the
+  // step.
+  RunJavaScriptOrFail(
+      "onPresentingAnimationFrameCallback = gamepadFrameCallback");
   my_mock.TogglePrimaryTrigger(controller_index);
   WaitOnJavaScriptStep();
   EndTest();

chrome/test/data/xr/e2e_test_files/html/test_gamepad_button.html

@@ -37,7 +37,7 @@ View.
         return frameCounter - lastInputChangeFrame > 60;
       }
 
-      onPresentingAnimationFrameCallback = function() {
+      function gamepadFrameCallback() {
         if (index == -1) return;
         frameCounter++;
         var gp = navigator.getGamepads()[index];
@@ -52,12 +52,19 @@ View.
         }
         if (!pressed && gp.buttons[0].pressed == true) {
           pressed = true;
+          // Unregister the callback so that we don't call
+          // finishJavaScriptStep() multiple times without acking if the test
+          // code doesn't ack within a single frame.
+          onPresentingAnimationFrameCallback = null;
           finishJavaScriptStep();
         }
         if (pressed && gp.buttons[0].pressed == false) {
+          onPresentingAnimationFrameCallback = null;
           done();
         }
       }
+
+      onPresentingAnimationFrameCallback = gamepadFrameCallback;
     </script>
   </body>
 </html>