Use multiple shared memory buffers cyclically for audio capture.

media/audio/audio_output_device.cc

Index: media/audio/audio_output_device.cc
===================================================================
--- media/audio/audio_output_device.cc	(revision 186364)
+++ media/audio/audio_output_device.cc	(working copy)
@@ -30,7 +30,7 @@
   virtual void MapSharedMemory() OVERRIDE;
 
   // Called whenever we receive notifications about pending data.
-  virtual void Process(int pending_data) OVERRIDE;
+  virtual void Process(int pending_data, int index) OVERRIDE;
 
  private:
   AudioRendererSink::RenderCallback* render_callback_;
@@ -48,6 +48,7 @@
       stream_id_(0),
       state_(IDLE),
       play_on_start_(true),
+      audio_thread_(false),
       stopping_hack_(false) {
   CHECK(ipc_);
 }
@@ -257,7 +258,8 @@
     AudioRendererSink::RenderCallback* render_callback)
     : AudioDeviceThread::Callback(audio_parameters,
                                   memory,
-                                  memory_length),
+                                  memory_length,
+                                  1),
       render_callback_(render_callback) {
 }
 
@@ -265,6 +267,7 @@
 }
 
 void AudioOutputDevice::AudioThreadCallback::MapSharedMemory() {
+  CHECK_EQ(total_segments_, 1);
   CHECK(shared_memory_.Map(TotalSharedMemorySizeInBytes(memory_length_)));
 
   // Calculate output and input memory size.
@@ -291,7 +294,8 @@
 }
 
 // Called whenever we receive notifications about pending data.
-void AudioOutputDevice::AudioThreadCallback::Process(int pending_data) {
+void AudioOutputDevice::AudioThreadCallback::Process(
+    int pending_data, int index) {
   if (pending_data == kPauseMark) {
     memset(shared_memory_.memory(), 0, memory_length_);
     SetActualDataSizeInBytes(&shared_memory_, memory_length_, 0);