Disable race dependent test

webrtc/video/video_send_stream_tests.cc

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include <algorithm>  // max
@@ skipping 1858 matching lines @@
   class NoFlexibleMode : public VP9HeaderObeserver {
     void InspectHeader(RTPVideoHeaderVP9* vp9videoHeader) override {
       EXPECT_FALSE(vp9videoHeader->flexible_mode);
       observation_complete_->Set();
     }
   } test;
 
   RunBaseTest(&test);
 }
 
-TEST_F(VideoSendStreamTest, VP9FlexMode) {
+TEST_F(VideoSendStreamTest, DISABLED_VP9FlexMode) {
   class FlexibleMode : public VP9HeaderObeserver {
     void ModifyConfigsHook(
         VideoSendStream::Config* send_config,
         std::vector<VideoReceiveStream::Config>* receive_configs,
         VideoEncoderConfig* encoder_config) override {
       vp9_settings_.flexibleMode = true;
     }
 
     void InspectHeader(RTPVideoHeaderVP9* vp9videoHeader) override {
       EXPECT_TRUE(vp9videoHeader->flexible_mode);
       observation_complete_->Set();
     }
 
   } test;
 
   RunBaseTest(&test);
 }
 
 }  // namespace webrtc