Disable MediaTest.VideoBearWavAlaw on Linux

The test is still flaky on Linux. See https://analysis.chromium.org/p/chromium/flake-portal/flakes/occurrences?key=ag9zfmZpbmRpdC1mb3ItbWVyQwsSBUZsYWtlIjhjaHJvbWl1bUBjb250ZW50X2Jyb3dzZXJ0ZXN0c0BNZWRpYVRlc3QuVmlkZW9CZWFyV2F2QWxhdww

TBR=armax@chromium.org

Bug: 979259
Change-Id: Ie92033cfe3b0d135fc27debe6514dd2227b4d0c1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1713590Reviewed-by: Yi Gu <yigu@chromium.org>
Commit-Queue: Yi Gu <yigu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#679758}

content/browser/media/media_browsertest.cc

@@ -280,7 +280,13 @@ IN_PROC_BROWSER_TEST_P(MediaTest, AudioBearFlacOgg) {
   PlayVideo("bear-flac.ogg", GetParam());
 }
 
-IN_PROC_BROWSER_TEST_P(MediaTest, VideoBearWavAlaw) {
+// Flaky on Linux. See https://crbug.com/979259
+#if defined(OS_LINUX)
+#define MAYBE_VideoBearWavAlaw DISABLED_VideoBearWavAlaw
+#else
+#define MAYBE_VideoBearWavAlaw VideoBearWavAlaw
+#endif
+IN_PROC_BROWSER_TEST_P(MediaTest, MAYBE_VideoBearWavAlaw) {
   PlayAudio("bear_alaw.wav", GetParam());
 }