Add a general PostProcessorUnittest.

chromecast/public/media/audio_post_processor_shlib.h

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROMECAST_PUBLIC_MEDIA_AUDIO_POST_PROCESSOR_SHLIB_H_
 #define CHROMECAST_PUBLIC_MEDIA_AUDIO_POST_PROCESSOR_SHLIB_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 14 matching lines @@
 // Called from StreamMixerAlsa when shared objects are listed in
 // /etc/cast_audio.json
 // AudioPostProcessors are created on startup and only destroyed/reset
 // if the output sample rate changes.
 extern "C" CHROMECAST_EXPORT chromecast::media::AudioPostProcessor*
 AudioPostProcessorShlib_Create(const std::string& config, int channels);
 
 namespace chromecast {
 namespace media {
 
+// The maximum amount of data that will ever be processed in one call.
+const int kMaxAudioWriteTimeMilliseconds = 20;
+
 // Interface for AudioPostProcessors used for applying DSP in StreamMixerAlsa.
 class AudioPostProcessor {
  public:
   // Updates the sample rate of the processor.
   // Returns |false| if the processor cannot support |sample_rate|
   // Returning false will result in crashing cast_shell.
   virtual bool SetSampleRate(int sample_rate) = 0;
 
   // Processes audio frames from |data|, overwriting contents.
   // |data| will always be 32-bit interleaved float.
@@ skipping 23 matching lines @@
   // OEM's do not need to implement this method.
   virtual void UpdateParameters(const std::string& message) {}
 
   virtual ~AudioPostProcessor() = default;
 };
 
 }  // namespace media
 }  // namespace chromecast
 
 #endif  // CHROMECAST_PUBLIC_MEDIA_AUDIO_POST_PROCESSOR_SHLIB_H_