Add aecdump support to audioproc_f.

webrtc/common_audio/wav_file.h

Index: webrtc/common_audio/wav_file.h
diff --git a/webrtc/common_audio/wav_file.h b/webrtc/common_audio/wav_file.h
index 2eadd3f7752bb29eb1a62fcf2aa355a837d7d6e6..42b0618e9cbe7a1511af34190809ed9e7d75e64f 100644
--- a/webrtc/common_audio/wav_file.h
+++ b/webrtc/common_audio/wav_file.h
@@ -29,6 +29,9 @@ class WavFile {
   virtual int sample_rate() const = 0;
   virtual int num_channels() const = 0;
   virtual uint32_t num_samples() const = 0;
+
+  // Returns a human-readable string containing the audio format.
+  std::string FormatAsString() const;
 };
 
 // Simple C++ class for writing 16-bit PCM WAV files. All error handling is