Restore sample_rate_hz() until Chromium is updated to not use it.

TBR=bjornv
TESTED=Chromium builds against webrtc head.
BUG=2894

Review URL: https://webrtc-codereview.appspot.com/12349004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5962 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_processing/include/audio_processing.h b/webrtc/modules/audio_processing/include/audio_processing.h
index ecd4187..6db1d12 100644
--- a/webrtc/modules/audio_processing/include/audio_processing.h
+++ b/webrtc/modules/audio_processing/include/audio_processing.h
@@ -195,10 +195,11 @@
   // DEPRECATED.
   // TODO(ajm): Remove after Chromium has upgraded to using Initialize().
   virtual int set_sample_rate_hz(int rate) = 0;
-  // DEPRECATED.
   // TODO(ajm): Remove after voice engine no longer requires it to resample
   // the reverse stream to the forward rate.
   virtual int input_sample_rate_hz() const = 0;
+  // TODO(ajm): Remove after Chromium no longer depends on it.
+  virtual int sample_rate_hz() const = 0;
 
   // TODO(ajm): Only intended for internal use. Make private and friend the
   // necessary classes?