Reverted the code for the non-interactive audible tab notification

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 <utility>
 
 #include "base/bind.h"
@@ skipping 35 matching lines @@
     clock_.Advance(base::TimeDelta::FromSeconds(1000000));
   }
 
   void SetUp() override {
     RenderViewHostTestHarness::SetUp();
 
     WebContentsImpl* web_contents = reinterpret_cast<WebContentsImpl*>(
         RenderViewHostTestHarness::web_contents());
     web_contents->SetDelegate(&mock_web_contents_delegate_);
 
-    AudioStateProvider* provider =  web_contents->audio_state_provider();
-    ASSERT_TRUE(provider);
-
-    monitor_ = provider->audio_stream_monitor();
-    ASSERT_TRUE(monitor_);
-
+    monitor_ = web_contents->audio_stream_monitor();
     const_cast<base::TickClock*&>(monitor_->clock_) = &clock_;
   }
 
   base::TimeTicks GetTestClockTime() { return clock_.NowTicks(); }
 
   void AdvanceClock(const base::TimeDelta& delta) { clock_.Advance(delta); }
 
   AudioStreamMonitor::ReadPowerAndClipCallback CreatePollCallback(
       int stream_id) {
     return base::Bind(
@@ skipping 222 matching lines @@
   StartMonitoring(
       kAnotherRenderProcessId, kStreamId, CreatePollCallback(kStreamId));
   ExpectIsPolling(kRenderProcessId, kStreamId, true);
   ExpectIsPolling(kAnotherRenderProcessId, kStreamId, true);
   StopMonitoring(kAnotherRenderProcessId, kStreamId);
   ExpectIsPolling(kRenderProcessId, kStreamId, true);
   ExpectIsPolling(kAnotherRenderProcessId, kStreamId, false);
 }
 
 }  // namespace content