Reland 153623004: Remove the unified IO code on the browser

content/browser/renderer_host/media/audio_sync_reader.cc

Index: content/browser/renderer_host/media/audio_sync_reader.cc
diff --git a/content/browser/renderer_host/media/audio_sync_reader.cc b/content/browser/renderer_host/media/audio_sync_reader.cc
index a51d3d1e35702432f55ca927de219593fcf4239b..d491fe2ec90df9a67089bfa82d84712fcd7d3e94 100644
--- a/content/browser/renderer_host/media/audio_sync_reader.cc
+++ b/content/browser/renderer_host/media/audio_sync_reader.cc
@@ -18,10 +18,8 @@ using media::AudioBus;
 namespace content {
 
 AudioSyncReader::AudioSyncReader(base::SharedMemory* shared_memory,
-                                 const media::AudioParameters& params,
-                                 int input_channels)
+                                 const media::AudioParameters& params)
     : shared_memory_(shared_memory),
-      input_channels_(input_channels),
       mute_audio_(CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kMuteAudio)),
       packet_size_(shared_memory_->requested_size()),
@@ -34,18 +32,7 @@ AudioSyncReader::AudioSyncReader(base::SharedMemory* shared_memory,
       maximum_wait_time_(base::TimeDelta::FromMilliseconds(20)),
 #endif
       buffer_index_(0) {
-  int input_memory_size = 0;
-  int output_memory_size = AudioBus::CalculateMemorySize(params);
-  if (input_channels_ > 0) {
-    // The input storage is after the output storage.
-    int frames = params.frames_per_buffer();
-    input_memory_size = AudioBus::CalculateMemorySize(input_channels_, frames);
-    char* input_data =
-        static_cast<char*>(shared_memory_->memory()) + output_memory_size;
-    input_bus_ = AudioBus::WrapMemory(input_channels_, frames, input_data);
-    input_bus_->Zero();
-  }
-  DCHECK_EQ(packet_size_, output_memory_size + input_memory_size);
+  DCHECK_EQ(packet_size_, AudioBus::CalculateMemorySize(params));
   output_bus_ = AudioBus::WrapMemory(params, shared_memory->memory());
   output_bus_->Zero();
 }
@@ -79,15 +66,6 @@ void AudioSyncReader::Read(const AudioBus* source, AudioBus* dest) {
     return;
   }
 
-  // Copy optional synchronized live audio input for consumption by renderer
-  // process.
-  if (input_bus_) {
-    if (source)
-      source->CopyTo(input_bus_.get());
-    else
-      input_bus_->Zero();
-  }
-
   if (mute_audio_)
     dest->Zero();
   else