Resampler modifications in preparation for arbitrary audioproc rates.

- Templatize PushResampler to support int16 and float.
- Add a helper method to PushSincResampler to compute the algorithmic
delay.

This is a prerequisite of:
http://review.webrtc.org/9919004/

BUG=2894
R=turaj@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/12169004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5943 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/voice_engine/transmit_mixer.h

@@ -200,7 +200,7 @@ private:
     // owns
     MonitorModule _monitorModule;
     AudioFrame _audioFrame;
-    PushResampler resampler_;  // ADM sample rate -> mixing rate
+    PushResampler<int16_t> resampler_;  // ADM sample rate -> mixing rate
     FilePlayer* _filePlayerPtr;
     FileRecorder* _fileRecorderPtr;
     FileRecorder* _fileCallRecorderPtr;