Sheriff: Disable WebRtcSimulcastBrowserTest.TestVgaReturnsTwoSimulcastStreams on Mac

TBR=hta@chromium.org

Bug: 1004546
Change-Id: I9b93678188ecb8743677fbc5912ae70f9b483377
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1808660Reviewed-by: Fergus Dall <sidereal@google.com>
Cr-Commit-Position: refs/heads/master@{#697081}

chrome/browser/media/webrtc/webrtc_simulcast_browsertest.cc

@@ -43,10 +43,12 @@ class WebRtcSimulcastBrowserTest : public WebRtcTestBase {
   }
 };
 
-// Fails/times out on Windows and Chrome OS. Flaky on Linux.
+// Fails/times out on Windows and Chrome OS. Flaky on Mac.
 // http://crbug.com/452623
+// http://crbug.com/1004546
 // MSan reports errors. http://crbug.com/452892
-#if defined(OS_WIN) || defined(OS_CHROMEOS) || defined(MEMORY_SANITIZER)
+#if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_CHROMEOS) || \
+    defined(MEMORY_SANITIZER)
 #define MAYBE_TestVgaReturnsTwoSimulcastStreams DISABLED_TestVgaReturnsTwoSimulcastStreams
 #else
 #define MAYBE_TestVgaReturnsTwoSimulcastStreams TestVgaReturnsTwoSimulcastStreams