[Chromecast] Don't use real audio config in mixer unit tests

Bug: internal b/168149351
Test: cast_audio_backend_unittests
Change-Id: I4172e243bc514888d127f56c8dfa83e83f9d60ac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2407057Reviewed-by: Yuchen Liu <yucliu@chromium.org>
Commit-Queue: Kenneth MacKay <kmackay@chromium.org>
Cr-Commit-Position: refs/heads/master@{#806416}

chromecast/media/cma/backend/mixer/stream_mixer.cc

@@ -159,12 +159,14 @@ StreamMixer::StreamMixer(
     : StreamMixer(nullptr,
                   std::make_unique<base::Thread>("CMA mixer"),
                   nullptr,
+                  "",
                   std::move(io_task_runner)) {}
 
 StreamMixer::StreamMixer(
     std::unique_ptr<MixerOutputStream> output,
     std::unique_ptr<base::Thread> mixer_thread,
     scoped_refptr<base::SingleThreadTaskRunner> mixer_task_runner,
+    const std::string& pipeline_json,
     scoped_refptr<base::SequencedTaskRunner> io_task_runner)
     : output_(std::move(output)),
       post_processing_pipeline_factory_(
@@ -226,8 +228,8 @@ StreamMixer::StreamMixer(
     LOG(INFO) << "Setting fixed sample rate to " << fixed_output_sample_rate_;
   }
 
-  CreatePostProcessors([](bool, const std::string&) {},
-                       "" /* override_config */, kDefaultInputChannels);
+  CreatePostProcessors([](bool, const std::string&) {}, pipeline_json,
+                       kDefaultInputChannels);
   mixer_pipeline_->SetPlayoutChannel(playout_channel_);
 
   // TODO(jyw): command line flag for filter frame alignment.

chromecast/media/cma/backend/mixer/stream_mixer.h

@@ -122,6 +122,7 @@ class StreamMixer {
       std::unique_ptr<MixerOutputStream> output,
       std::unique_ptr<base::Thread> mixer_thread,
       scoped_refptr<base::SingleThreadTaskRunner> mixer_task_runner,
+      const std::string& pipeline_json,
       scoped_refptr<base::SequencedTaskRunner> io_task_runner = nullptr);
   void ResetPostProcessorsForTest(
       std::unique_ptr<PostProcessingPipelineFactory> pipeline_factory,

chromecast/media/cma/backend/mixer/stream_mixer_external_audio_pipeline_unittest.cc

@@ -82,8 +82,8 @@ class ExternalAudioPipelineTest : public ::testing::Test {
     // Set that external library is supported.
     external_audio_pipeline_support_->SetSupported();
 
-    mixer_ = std::make_unique<StreamMixer>(nullptr, nullptr,
-                                           base::ThreadTaskRunnerHandle::Get());
+    mixer_ = std::make_unique<StreamMixer>(
+        nullptr, nullptr, base::ThreadTaskRunnerHandle::Get(), "{}");
   }
 
   void TearDown() override {

chromecast/media/cma/backend/mixer/stream_mixer_unittest.cc

@@ -378,8 +378,8 @@ class StreamMixerTest : public testing::Test {
   StreamMixerTest() {
     auto output = std::make_unique<NiceMock<MockMixerOutput>>();
     mock_output_ = output.get();
-    mixer_ = std::make_unique<StreamMixer>(std::move(output), nullptr,
-                                           base::ThreadTaskRunnerHandle::Get());
+    mixer_ = std::make_unique<StreamMixer>(
+        std::move(output), nullptr, base::ThreadTaskRunnerHandle::Get(), "{}");
     mixer_->SetVolume(AudioContentType::kMedia, 1.0f);
     mixer_->SetVolume(AudioContentType::kAlarm, 1.0f);
     std::string test_pipeline_json = base::StringPrintf(