Allow AudioRendererMixerInputs to be restarted after stopped.

content/renderer/media/audio_renderer_mixer_manager_unittest.cc

 // Copyright (c) 2012 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 "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "content/renderer/media/audio_renderer_mixer_manager.h"
 #include "ipc/ipc_message.h"
 #include "media/audio/audio_parameters.h"
@@ skipping 115 matching lines @@
   // each.  Note: Under normal conditions, each mixer would get its own sink!
   EXPECT_CALL(*mock_sink_.get(), Start()).Times(2);
   EXPECT_CALL(*mock_sink_.get(), Stop()).Times(2);
 
   media::AudioParameters params(
       media::AudioParameters::AUDIO_PCM_LINEAR, kChannelLayout, kSampleRate,
       kBitsPerChannel, kBufferSize);
 
   // Create two mixer inputs and ensure this doesn't instantiate any mixers yet.
   EXPECT_EQ(mixer_count(), 0);
+  media::FakeAudioRenderCallback callback(0);
   scoped_refptr<media::AudioRendererMixerInput> input(
       manager_->CreateInput(kRenderViewId, kRenderFrameId));
+  input->Initialize(params, &callback);
   EXPECT_EQ(mixer_count(), 0);
+  media::FakeAudioRenderCallback another_callback(1);
   scoped_refptr<media::AudioRendererMixerInput> another_input(
       manager_->CreateInput(kAnotherRenderViewId, kAnotherRenderFrameId));
+  another_input->Initialize(params, &another_callback);
   EXPECT_EQ(mixer_count(), 0);
 
   // Implicitly test that AudioRendererMixerInput was provided with the expected
   // callbacks needed to acquire an AudioRendererMixer and remove it.
-  media::FakeAudioRenderCallback callback(0);
-  input->Initialize(params, &callback);
+  input->Start();
   EXPECT_EQ(mixer_count(), 1);
-  media::FakeAudioRenderCallback another_callback(1);
-  another_input->Initialize(params, &another_callback);
+  another_input->Start();
   EXPECT_EQ(mixer_count(), 2);
 
   // Destroying the inputs should destroy the mixers.
   input->Stop();
   input = NULL;
   EXPECT_EQ(mixer_count(), 1);
   another_input->Stop();
   another_input = NULL;
   EXPECT_EQ(mixer_count(), 0);
 }
 
 }  // namespace content