[Chromecast] cma: mixer: Don't fail on non-float audio buffers

If audio stream is not in float format we can process audio buffers by
taking the same route as an audio data processing. This can happen if
audio buffers are supplied within the same process and we are using
external buffer pool.

Bug: internal b/159173611
Test: cast_audio_backend_unittests; run GVA config on the reference device
Signed-off-by: Volodymyr Riazantsev <riazantsevv@google.com>
Change-Id: I0548fc81960313f95f1c609f9e3676da0af3774e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2391284Reviewed-by: Kenneth MacKay <kmackay@chromium.org>
Cr-Commit-Position: refs/heads/master@{#804980}

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

@@ -358,7 +358,9 @@ bool MixerInputConnection::HandleAudioBuffer(
   }
 
   DCHECK_EQ(data - buffer->data(), kAudioMessageHeaderSize);
-  DCHECK_EQ(sample_format_, mixer_service::SAMPLE_FORMAT_FLOAT_P);
+  if (sample_format_ != mixer_service::SAMPLE_FORMAT_FLOAT_P) {
+    return HandleAudioData(data, size, timestamp);
+  }
 
   int32_t num_frames = size / (sizeof(float) * num_channels_);
   DCHECK_EQ(sizeof(int32_t), 4u);