[Chromecast] Store ALSA Mixer test data as uint32_t.

chromecast/media/cma/backend/alsa/mock_alsa_wrapper.cc

 // Copyright 2015 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.
 
 #include "chromecast/media/cma/backend/alsa/mock_alsa_wrapper.h"
 
 #include "base/logging.h"
 
 // Define dummy structs here to avoid linking in the ALSA lib.
 struct _snd_pcm_hw_params {};
 struct _snd_pcm {};
 
 namespace chromecast {
 namespace media {
 
+const size_t kBytesPerSample = sizeof(int32_t);
+const int kNumChannels = 2;
+
 // This class keeps basic state to ensure that ALSA is being used correctly.
 // Calls from MockAlsaWrapper are delegated to an instance of this class in
 // cases where internal ALSA state change occurs, or where a valid value needs
 // to be returned to the caller.
 class MockAlsaWrapper::FakeAlsaWrapper : public AlsaWrapper {
  public:
   FakeAlsaWrapper()
       : state_(SND_PCM_STATE_RUNNING),
         fake_handle_(nullptr),
         fake_pcm_hw_params_(nullptr) {}
@@ skipping 24 matching lines @@
     *handle = fake_handle_;
     return 0;
   }
 
   snd_pcm_sframes_t PcmWritei(snd_pcm_t* handle,
                               const void* buffer,
                               snd_pcm_uframes_t size) override {
     CHECK_EQ(fake_handle_, handle);
     CHECK(buffer);
     const uint8_t* ptr = reinterpret_cast<const uint8_t*>(buffer);
-    int len = size * 2 * 4;
+    int len = size * kNumChannels * kBytesPerSample;
     data_.assign(ptr, ptr + len);
     return size;
   }
 
   int PcmHwParamsMalloc(snd_pcm_hw_params_t** ptr) override {
     fake_pcm_hw_params_ = new snd_pcm_hw_params_t();
     CHECK(fake_pcm_hw_params_);
     *ptr = fake_pcm_hw_params_;
     return 0;
   }
 
   ssize_t PcmFormatSize(snd_pcm_format_t format, size_t samples) override {
-    return 4 * samples;
+    return kBytesPerSample * samples;
   };
 
   snd_pcm_state_t state() { return state_; }
   std::vector<uint8_t>& data() { return data_; }
 
  private:
   snd_pcm_state_t state_;
   snd_pcm_t* fake_handle_;
   snd_pcm_hw_params_t* fake_pcm_hw_params_;
   std::vector<uint8_t> data_;
@@ skipping 27 matching lines @@
 snd_pcm_state_t MockAlsaWrapper::state() {
   return fake_->state();
 }
 
 const std::vector<uint8_t>& MockAlsaWrapper::data() {
   return fake_->data();
 }
 
 }  // namespace media
 }  // namespace chromecast