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/include/mock_audio_processing.h

@@ -209,8 +209,15 @@ class MockAudioProcessing : public AudioProcessing {
       bool());
   MOCK_METHOD1(ProcessStream,
       int(AudioFrame* frame));
+  MOCK_METHOD5(ProcessStream,
+      int(float* const* data, int frames, int sample_rate_hz,
+          ChannelLayout input_layout,
+          ChannelLayout output_layout));
   MOCK_METHOD1(AnalyzeReverseStream,
       int(AudioFrame* frame));
+  MOCK_METHOD4(AnalyzeReverseStream,
+      int(const float* const* data, int frames, int sample_rate_hz,
+          ChannelLayout input_layout));
   MOCK_METHOD1(set_stream_delay_ms,
       int(int delay));
   MOCK_CONST_METHOD0(stream_delay_ms,
@@ -242,16 +249,16 @@ class MockAudioProcessing : public AudioProcessing {
   }
   virtual MockHighPassFilter* high_pass_filter() const {
     return high_pass_filter_.get();
-  };
+  }
   virtual MockLevelEstimator* level_estimator() const {
     return level_estimator_.get();
-  };
+  }
   virtual MockNoiseSuppression* noise_suppression() const {
     return noise_suppression_.get();
-  };
+  }
   virtual MockVoiceDetection* voice_detection() const {
     return voice_detection_.get();
-  };
+  }
 
  private:
   scoped_ptr<MockEchoCancellation> echo_cancellation_;