Add a deinterleaved float interface to AudioProcessing.

This is mainly to support the native audio format in Chrome. Although
this implementation just moves the float->int conversion under the hood,
we will transition AudioProcessing towards supporting this format
throughout.

- Add a test which verifies we get identical output with the float and
int interfaces.
- The float and int wrappers are tasked with conversion to the
AudioBuffer format. A new shared Process/Analyze method does most of
the work.
- Add a new field to the debug.proto to hold deinterleaved data.
- Add helpers to audio_utils.cc, and start using numeric_limits.
- Note that there was no performance difference between numeric_limits
and a literal value when measured on Linux using gcc or clang.

BUG=2894
R=aluebs@webrtc.org, bjornv@webrtc.org, henrikg@webrtc.org, tommi@webrtc.org, turaj@webrtc.org, xians@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/9179004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5641 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/audio_processing/audio_processing_impl.h

@@ -63,7 +63,16 @@ class AudioProcessingImpl : public AudioProcessing {
   virtual void set_output_will_be_muted(bool muted) OVERRIDE;
   virtual bool output_will_be_muted() const OVERRIDE;
   virtual int ProcessStream(AudioFrame* frame) OVERRIDE;
+  virtual int ProcessStream(float* const* data,
+                            int samples_per_channel,
+                            int sample_rate_hz,
+                            ChannelLayout input_layout,
+                            ChannelLayout output_layout) OVERRIDE;
   virtual int AnalyzeReverseStream(AudioFrame* frame) OVERRIDE;
+  virtual int AnalyzeReverseStream(const float* const* data,
+                                   int samples_per_channel,
+                                   int sample_rate_hz,
+                                   ChannelLayout layout) OVERRIDE;
   virtual int set_stream_delay_ms(int delay) OVERRIDE;
   virtual int stream_delay_ms() const OVERRIDE;
   virtual bool was_stream_delay_set() const OVERRIDE;
@@ -89,8 +98,11 @@ class AudioProcessingImpl : public AudioProcessing {
  private:
   int MaybeInitializeLocked(int sample_rate_hz, int num_input_channels,
                             int num_output_channels, int num_reverse_channels);
+  int ProcessStreamLocked();
+  int AnalyzeReverseStreamLocked();
+
   bool is_data_processed() const;
-  bool interleave_needed(bool is_data_processed) const;
+  bool output_copy_needed(bool is_data_processed) const;
   bool synthesis_needed(bool is_data_processed) const;
   bool analysis_needed(bool is_data_processed) const;