Getting rid of AudioHardwareConfig and its synchronous IPC.

content/renderer/media/audio_renderer_sink_cache_unittest.cc

Index: content/renderer/media/audio_renderer_sink_cache_unittest.cc
diff --git a/content/renderer/media/audio_renderer_sink_cache_unittest.cc b/content/renderer/media/audio_renderer_sink_cache_unittest.cc
index 81e349c24fa126f183743e9ee06ca4dd4276819a..ea5564b9eb2236a5cfdb711b97ce6365b06564fc 100644
--- a/content/renderer/media/audio_renderer_sink_cache_unittest.cc
+++ b/content/renderer/media/audio_renderer_sink_cache_unittest.cc
@@ -284,6 +284,29 @@ TEST_F(AudioRendererSinkCacheTest, ReleaseSinkBeforeScheduledDeletion) {
   EXPECT_EQ(0, sink_count());
 }
 
+// Verify that default output devicee information can be retrieved after default
+// sink deletion without creating another default sink.
+TEST_F(AudioRendererSinkCacheTest, DefaultOutputDeviceInfoCached) {
+  EXPECT_EQ(0, sink_count());
+
+  media::OutputDeviceInfo device_info =
+      cache_->GetSinkInfo(kRenderFrameId, 0, kDefaultDeviceId, url::Origin());
+  EXPECT_EQ(1, sink_count());  // This sink is scheduled for deletion now.
+
+  base::Thread thread("timeout_thread");
+  thread.Start();
+
+  // 100 ms more than garbage collection timeout.
+  WaitOnAnotherThread(thread, kDeleteTimeoutMs + 100);
+
+  EXPECT_EQ(0, sink_count());  // Default sink is deleted.
+
+  media::OutputDeviceInfo another_device_info =
+      cache_->GetSinkInfo(kRenderFrameId, 0, kDefaultDeviceId, url::Origin());
+
+  EXPECT_EQ(0, sink_count());  // No new default sink is created.
+}
+
 // Check that a sink created on one thread in response to GetSinkInfo can be
 // used on another thread.
 TEST_F(AudioRendererSinkCacheTest, MultithreadedAccess) {