Suppress QueueTimelineTests.MapRead_OnWorkDone

Suppresses QueueTimelineTests.MapRead_OnWorkDone on Metal since it has
been flaking occasionally on real hardware.

Bug: 454668181
Change-Id: Ic1d88a99e029f8d9c8b88e423286eeb060570c35
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/268435
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Commit-Queue: Kai Ninomiya <kainino@chromium.org>
Auto-Submit: Brian Sheedy <bsheedy@google.com>

src/dawn/tests/end2end/QueueTimelineTests.cpp

diff --git a/src/dawn/tests/end2end/QueueTimelineTests.cpp b/src/dawn/tests/end2end/QueueTimelineTests.cpp
index 84def86..baa55ce 100644
--- a/src/dawn/tests/end2end/QueueTimelineTests.cpp
+++ b/src/dawn/tests/end2end/QueueTimelineTests.cpp
@@ -61,6 +61,9 @@
 // when queue.OnSubmittedWorkDone is called after mMapReadBuffer.MapAsync. The callback order should
 // happen in the order the functions are called.
 TEST_P(QueueTimelineTests, MapRead_OnWorkDone) {
+    // TODO(crbug.com/454668181): Flakily fails on Mac w/ Metal.
+    DAWN_SUPPRESS_TEST_IF(IsMetal());
+
     MockMapAsyncCallback mockMapAsyncCb;
     MockQueueWorkDoneCallback mockQueueWorkDoneCb;