Making AudioManagerBase::ShutdownOnAudioThread() platform-agnostic

media/audio/mac/audio_manager_mac.cc

Index: media/audio/mac/audio_manager_mac.cc
diff --git a/media/audio/mac/audio_manager_mac.cc b/media/audio/mac/audio_manager_mac.cc
index 8478e0f70c56e5aded802dd0a8182f25dd605a35..ff66262a9cae2dfb3991ae6e555da140b259a668 100644
--- a/media/audio/mac/audio_manager_mac.cc
+++ b/media/audio/mac/audio_manager_mac.cc
@@ -530,6 +530,26 @@ void AudioManagerMac::ShutdownOnAudioThread() {
   // APIs and they can fail and disrupt tests during shutdown.
   in_shutdown_ = true;
   AudioManagerBase::ShutdownOnAudioThread();

[alokp, 2017/07/14 18:58:53]

nit: May be release base class resources *after* local resources to be
consistent with the ways destructors work?

+
+  // Even if tasks to close the streams are enqueued, they would not run
+  // leading to CHECKs getting hit in the destructor about open streams. Close
+  // them explicitly here. crbug.com/608049.
+  for (auto iter = basic_input_streams_.begin();
+       iter != basic_input_streams_.end();) {
+    // Note: Closing the stream will invalidate the iterator.
+    // Increment the iterator before closing the stream.
+    AudioInputStream* stream = *iter++;
+    stream->Close();
+  }
+  for (auto iter = low_latency_input_streams_.begin();
+       iter != low_latency_input_streams_.end();) {
+    // Note: Closing the stream will invalidate the iterator.
+    // Increment the iterator before closing the stream.
+    AudioInputStream* stream = *iter++;
+    stream->Close();
+  }
+  CHECK(basic_input_streams_.empty());
+  CHECK(low_latency_input_streams_.empty());
 }
 
 bool AudioManagerMac::HasAudioOutputDevices() {