Disable RTCRtpSenderTest.ReplaceTrackSetsTrack

Disables RTCRtpSenderTest.ReplaceTrackSetsTrack on Android and Linux
due to flaky behavior.

BUG=800465

TBR=sergeyu@chromium.org

Change-Id: I1c0f3864d2d60b81b34a9718ead8e1c9f5c94cff
Reviewed-on: https://chromium-review.googlesource.com/927535
Commit-Queue: Donn Denman <donnd@chromium.org>
Reviewed-by: Donn Denman <donnd@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537919}

content/renderer/media/webrtc/rtc_rtp_sender_unittest.cc

@@ -125,6 +125,13 @@ TEST_F(RTCRtpSenderTest, CreateSenderWithNullTrack) {
   EXPECT_TRUE(sender_->Track().IsNull());
 }
 
+// This test is flaky on Android and Linux.
+// See crbug.com/800465 for detail.
+#if defined(OS_ANDROID) || defined(OS_LINUX)
+#define MAYBE_ReplaceTrackSetsTrack DISABLED_ReplaceTrackSetsTrack
+#else
+#define MAYBE_ReplaceTrackSetsTrack ReplaceTrackSetsTrack
+#endif
 TEST_F(RTCRtpSenderTest, ReplaceTrackSetsTrack) {
   auto web_track1 = CreateWebTrack("track1");
   sender_ = CreateSender(web_track1);