Add keyboard channel support to AudioBuffer.

Also use local aliases for AudioBuffers for brevity.

BUG=2894
R=aluebs@webrtc.org, bjornv@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/13369005

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5973 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_processing/audio_buffer.h b/webrtc/modules/audio_processing/audio_buffer.h
index 45e62a4..eaf53eb 100644
--- a/webrtc/modules/audio_processing/audio_buffer.h
+++ b/webrtc/modules/audio_processing/audio_buffer.h
@@ -53,6 +53,7 @@
   int num_channels() const;
   int samples_per_channel() const;
   int samples_per_split_channel() const;
+  int samples_per_keyboard_channel() const;
 
   int16_t* data(int channel) const;
   int16_t* low_pass_split_data(int channel) const;
@@ -60,6 +61,7 @@
   int16_t* mixed_data(int channel) const;
   int16_t* mixed_low_pass_data(int channel) const;
   int16_t* low_pass_reference(int channel) const;
+  const float* keyboard_data() const;
 
   SplitFilterStates* filter_states(int channel) const;
 
@@ -106,6 +108,7 @@
   bool is_muted_;
 
   int16_t* data_;
+  const float* keyboard_data_;
   scoped_ptr<ChannelBuffer<int16_t> > channels_;
   scoped_ptr<SplitChannelBuffer> split_channels_;
   scoped_ptr<SplitFilterStates[]> filter_states_;