Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/cras/cras_unified_unittest.cc

Index: media/audio/cras/cras_unified_unittest.cc
diff --git a/media/audio/cras/cras_unified_unittest.cc b/media/audio/cras/cras_unified_unittest.cc
index 89a3ef0b8a39efbe9a0ec23cc0a7ad304955d017..52fe11ad3149f786889b2b59a50f63c621e17fcc 100644
--- a/media/audio/cras/cras_unified_unittest.cc
+++ b/media/audio/cras/cras_unified_unittest.cc
@@ -63,7 +63,11 @@ class CrasUnifiedStreamTest : public testing::Test {
     base::RunLoop().RunUntilIdle();
   }
 
-  ~CrasUnifiedStreamTest() override {}
+  ~CrasUnifiedStreamTest() override {
+    mock_manager_->GetTaskRunner()->PostTask(
+        FROM_HERE, base::Bind(&media::AudioManager::Shutdown,
+                              base::Unretained(mock_manager_.get())));
+  }
 
   CrasUnifiedStream* CreateStream(ChannelLayout layout) {
     return CreateStream(layout, kTestFramesPerPacket);
@@ -88,8 +92,7 @@ class CrasUnifiedStreamTest : public testing::Test {
   static const uint32_t kTestFramesPerPacket;
 
   base::TestMessageLoop message_loop_;
-  std::unique_ptr<StrictMock<MockAudioManagerCras>, AudioManagerDeleter>
-      mock_manager_;
+  std::unique_ptr<StrictMock<MockAudioManagerCras>> mock_manager_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(CrasUnifiedStreamTest);