Fix accessing uninitialized variables when not processing a reverse stream.

TBR=turaj@webrtc.org

Review URL: https://codereview.webrtc.org/1306863003 .

Cr-Commit-Position: refs/heads/master@{#9758}
diff --git a/webrtc/modules/audio_processing/test/audioproc_float.cc b/webrtc/modules/audio_processing/test/audioproc_float.cc
index f22c41e..268702e 100644
--- a/webrtc/modules/audio_processing/test/audioproc_float.cc
+++ b/webrtc/modules/audio_processing/test/audioproc_float.cc
@@ -168,12 +168,15 @@
   const StreamConfig output_config = {
       out_file.sample_rate(), out_buf.num_channels(),
   };
-  const StreamConfig reverse_input_config = {
-      in_rev_file->sample_rate(), in_rev_file->num_channels(),
-  };
-  const StreamConfig reverse_output_config = {
-      out_rev_file->sample_rate(), out_rev_file->num_channels(),
-  };
+
+  StreamConfig reverse_input_config = {};
+  StreamConfig reverse_output_config = {};
+  if (process_reverse) {
+    StreamConfig reverse_input_config = {in_rev_file->sample_rate(),
+                                         in_rev_file->num_channels()};
+    StreamConfig reverse_output_config = {out_rev_file->sample_rate(),
+                                          out_rev_file->num_channels()};
+  }
   while (in_file.ReadSamples(in_interleaved.size(),
                              &in_interleaved[0]) == in_interleaved.size()) {
     // Have logs display the file time rather than wallclock time.