Fix teardown of stale AudioStreamMonitor poll callbacks.

content/browser/media/audio_stream_monitor_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 "content/browser/media/audio_stream_monitor.h"
 
 #include <map>
 #include <memory>
 #include <utility>
 
@@ skipping 325 matching lines @@
   StartMonitoring(kRenderProcessId, kStreamId, CreatePollCallback(kStreamId));
   StartMonitoring(
       kAnotherRenderProcessId, kStreamId, CreatePollCallback(kStreamId));
   ExpectIsPolling(kRenderProcessId, kStreamId, true);
   ExpectIsPolling(kAnotherRenderProcessId, kStreamId, true);
   StopMonitoring(kAnotherRenderProcessId, kStreamId);
   ExpectIsPolling(kRenderProcessId, kStreamId, true);
   ExpectIsPolling(kAnotherRenderProcessId, kStreamId, false);
 }
 
+TEST_F(AudioStreamMonitorTest, RenderProcessGone) {
+  StartMonitoring(kRenderProcessId, kStreamId, CreatePollCallback(kStreamId));
+  StartMonitoring(kAnotherRenderProcessId, kStreamId,
+                  CreatePollCallback(kStreamId));
+  ExpectIsPolling(kRenderProcessId, kStreamId, true);
+  ExpectIsPolling(kAnotherRenderProcessId, kStreamId, true);
+  monitor_->RenderProcessGone(kRenderProcessId);
+  ExpectIsPolling(kRenderProcessId, kStreamId, false);
+  monitor_->RenderProcessGone(kAnotherRenderProcessId);
+  ExpectIsPolling(kAnotherRenderProcessId, kStreamId, false);
+}
+
 }  // namespace content