Disable 3 tests in media_browsertest.cc due to flakiness

TBR=hbos@chromium.org
NOTRY=true

Bug: 1001364
Change-Id: I84fc313f4e3467a0583119793568e285e987470c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1833284Reviewed-by: Xida Chen <xidachen@chromium.org>
Commit-Queue: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#701571}

content/browser/media/media_browsertest.cc

@@ -167,7 +167,8 @@ IN_PROC_BROWSER_TEST_P(MediaTest, DISABLED_VideoBearWebm) {
   PlayVideo("bear.webm", GetParam());
 }
 
-IN_PROC_BROWSER_TEST_P(MediaTest, AudioBearOpusWebm) {
+// crbug.com/1001364: disabled due to flakiness.
+IN_PROC_BROWSER_TEST_P(MediaTest, DISABLED_AudioBearOpusWebm) {
   PlayVideo("bear-opus.webm", GetParam());
 }
 
@@ -301,11 +302,13 @@ IN_PROC_BROWSER_TEST_P(MediaTest, MAYBE_VideoBearWavAlaw) {
   PlayAudio("bear_alaw.wav", GetParam());
 }
 
-IN_PROC_BROWSER_TEST_P(MediaTest, VideoBearWavMulaw) {
+// crbug.com/1001364: disabled due to flakiness.
+IN_PROC_BROWSER_TEST_P(MediaTest, DISABLED_VideoBearWavMulaw) {
   PlayAudio("bear_mulaw.wav", GetParam());
 }
 
-IN_PROC_BROWSER_TEST_P(MediaTest, VideoBearWavPcm) {
+// crbug.com/1001364: disabled due to flakiness.
+IN_PROC_BROWSER_TEST_P(MediaTest, DISABLED_VideoBearWavPcm) {
   PlayAudio("bear_pcm.wav", GetParam());
 }