WebXR - hit test intrumentation - increase retries to reduce flakiness

Bug: 1112333
Change-Id: I6be773adf04a41639865521a2eec02b66bd4989d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2335895Reviewed-by: Brian Sheedy <bsheedy@chromium.org>
Commit-Queue: Piotr Bialecki <bialpio@chromium.org>
Cr-Commit-Position: refs/heads/master@{#794592}

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

@@ -40,7 +40,9 @@ Tests that AR hit test results are available in rAF as soon as hit test source i
         // feature points, and then to actually finding the plane. Given that, we should allow
         // for retry logic in the test - the initial hit tests may return empty results until
         // ARCore detects a plane.
-        let retries_left = 30;
+        // Since we try every frame and we currently run at 30FPS, it should mean we'll retry for
+        // 5 seconds.
+        let retries_left = 30 * 5;
 
         onARFrameCallback = (session, frame) => {
           switch(testState) {