Getting rid of AudioHardwareConfig and its synchronous IPC.

content/renderer/media/audio_renderer_sink_cache_unittest.cc

 // Copyright 2016 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 <array>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/logging.h"
 #include "base/test/test_simple_task_runner.h"
@@ skipping 266 matching lines @@
   base::Thread thread("timeout_thread");
   thread.Start();
 
   // 100 ms more than garbage collection timeout.
   WaitOnAnotherThread(thread, kDeleteTimeoutMs + 100);
 
   // Nothing crashed and the second sink deleted on schedule.
   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) {
   EXPECT_EQ(0, sink_count());
 
   base::Thread thread1("thread1");
   thread1.Start();
 
   base::Thread thread2("thread2");
   thread2.Start();
@@ skipping 68 matching lines @@
   // Wait for completion of all the tasks posted to at least one thread.
   media::WaitableMessageLoopEvent loop_event(
       TestTimeouts::action_max_timeout());
   threads[kThreadCount - 1]->task_runner()->PostTaskAndReply(
       FROM_HERE, base::Bind(&base::DoNothing), loop_event.GetClosure());
   // Runs the loop and waits for the thread to call event's closure.
   loop_event.RunAndWait();
 }
 
 }  // namespace content