Introduce AudioOutputResampler for browser side resampling.

media/base/sinc_resampler.h

Index: media/base/sinc_resampler.h
diff --git a/media/base/sinc_resampler.h b/media/base/sinc_resampler.h
index 029a38a857dd466efddd4ca8faf97a783019ec8f..ef2f176b29bc84bc680e41731243f0c52a5dc9bb 100644
--- a/media/base/sinc_resampler.h
+++ b/media/base/sinc_resampler.h
@@ -35,6 +35,9 @@ class MEDIA_EXPORT SincResampler {
   // single call to |read_cb_| for more data.
   int ChunkSize();
 
+  // Flush all buffered data and reset internal indices.
+  void Flush();
+
  private:
   FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, Convolve);
   FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, ConvolveBenchmark);