Fix flaky cast_unittests where threads were being joined incorrectly.

media/cast/receiver/audio_decoder_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/synchronization/condition_variable.h"
 #include "base/synchronization/lock.h"
 #include "base/sys_byteorder.h"
 #include "base/time/time.h"
@@ skipping 17 matching lines @@
       : codec(c), num_channels(n), sampling_rate(s) {}
 };
 }  // namespace
 
 class AudioDecoderTest : public ::testing::TestWithParam<TestScenario> {
  public:
   AudioDecoderTest()
       : cast_environment_(new StandaloneCastEnvironment()),
         cond_(&lock_) {}
 
+  virtual ~AudioDecoderTest() {
+    // Make sure all threads have stopped before the environment goes away.
+    cast_environment_->Shutdown();
+  }
+
  protected:
   virtual void SetUp() OVERRIDE {
     audio_decoder_.reset(new AudioDecoder(cast_environment_,
                                           GetParam().num_channels,
                                           GetParam().sampling_rate,
                                           GetParam().codec));
     CHECK_EQ(STATUS_AUDIO_INITIALIZED, audio_decoder_->InitializationResult());
 
     audio_bus_factory_.reset(
         new TestAudioBusFactory(GetParam().num_channels,
@@ skipping 185 matching lines @@
     AudioDecoderTestScenarios,
     AudioDecoderTest,
     ::testing::Values(
          TestScenario(CODEC_AUDIO_PCM16, 1, 8000),
          TestScenario(CODEC_AUDIO_PCM16, 2, 48000),
          TestScenario(CODEC_AUDIO_OPUS, 1, 8000),
          TestScenario(CODEC_AUDIO_OPUS, 2, 48000)));
 
 }  // namespace cast
 }  // namespace media