Unpack different wav files after each INIT event of the aecdump

Some aecdumps have more than one INIT event. In those cases only the last wav file was unpacked, which sometimes is not the most interesting or desired one.
This CL creates a different wav file after each INIT event.

Review-Url: https://codereview.webrtc.org/2067423002
Cr-Commit-Position: refs/heads/master@{#13196}

webrtc/modules/audio_processing/test/unpack.cc

diff --git a/webrtc/modules/audio_processing/test/unpack.cc b/webrtc/modules/audio_processing/test/unpack.cc
index f5c0700..d3f1633 100644
--- a/webrtc/modules/audio_processing/test/unpack.cc
+++ b/webrtc/modules/audio_processing/test/unpack.cc
@@ -303,13 +303,19 @@
       if (!FLAGS_raw) {
         // The WAV files need to be reset every time, because they cant change
         // their sample rate or number of channels.
-        reverse_wav_file.reset(new WavWriter(FLAGS_reverse_file + ".wav",
+        std::stringstream reverse_name;
+        reverse_name << FLAGS_reverse_file << frame_count << ".wav";
+        reverse_wav_file.reset(new WavWriter(reverse_name.str(),
                                              reverse_sample_rate,
                                              num_reverse_channels));
-        input_wav_file.reset(new WavWriter(FLAGS_input_file + ".wav",
+        std::stringstream input_name;
+        input_name << FLAGS_input_file << frame_count << ".wav";
+        input_wav_file.reset(new WavWriter(input_name.str(),
                                            input_sample_rate,
                                            num_input_channels));
-        output_wav_file.reset(new WavWriter(FLAGS_output_file + ".wav",
+        std::stringstream output_name;
+        output_name << FLAGS_output_file << frame_count << ".wav";
+        output_wav_file.reset(new WavWriter(output_name.str(),
                                             output_sample_rate,
                                             num_output_channels));
       }