[Hotword] Adding audio parameters to handle audio coming from the DSP.

media/audio/cras/cras_input.cc

Index: media/audio/cras/cras_input.cc
diff --git a/media/audio/cras/cras_input.cc b/media/audio/cras/cras_input.cc
index 0b8644603f8996e670b988c282a1b234e4062ee0..bdb0261df49c0066239943678c8c030060a210e0 100644
--- a/media/audio/cras/cras_input.cc
+++ b/media/audio/cras/cras_input.cc
@@ -159,8 +159,19 @@ void CrasInputStream::Start(AudioInputCallback* callback) {
     return;
   }
 
-  unsigned int frames_per_packet = params_.frames_per_buffer();
-  cras_stream_params* stream_params = cras_client_stream_params_create(
+  // For a hotword hardware stream, only wait for a single callback.
+  // Replace the existing callback with the HotwordSampleReady one that should
+  // only run once.
+  if (params_.effects() & AudioParameters::PlatformEffectsMask::HOTWORD) {
+    if (cras_client_add_hotword_callback(client_, audio_format,
+                                         CrasInputStream::HotwordSampleReady)) {
+      DLOG(WARNING) << "Failed to add the hotword callback.";
+      callback_->OnError(this);
+      callback_ = NULL;
+    }
+  }else {
+    unsigned int frames_per_packet = params_.frames_per_buffer();
+    cras_stream_params* stream_params = cras_client_stream_params_create(
       stream_direction_,
       frames_per_packet,  // Total latency.
       frames_per_packet,  // Call back when this many ready.
@@ -171,23 +182,24 @@ void CrasInputStream::Start(AudioInputCallback* callback) {
       CrasInputStream::SamplesReady,
       CrasInputStream::StreamError,
       audio_format);
-  if (!stream_params) {
-    DLOG(WARNING) << "Error setting up stream parameters.";
-    callback_->OnError(this);
-    callback_ = NULL;
-    cras_audio_format_destroy(audio_format);
-    return;
-  }
-
-  // Before starting the stream, save the number of bytes in a frame for use in
-  // the callback.
-  bytes_per_frame_ = cras_client_format_bytes_per_frame(audio_format);
-
-  // Adding the stream will start the audio callbacks.
-  if (cras_client_add_stream(client_, &stream_id_, stream_params)) {
-    DLOG(WARNING) << "Failed to add the stream.";
-    callback_->OnError(this);
-    callback_ = NULL;
+    if (!stream_params) {
+      DLOG(WARNING) << "Error setting up stream parameters.";
+      callback_->OnError(this);
+      callback_ = NULL;
+      cras_audio_format_destroy(audio_format);
+      return;
+    }
+
+    // Before starting the stream, save the number of bytes in a frame for use
+    // in the callback.
+    bytes_per_frame_ = cras_client_format_bytes_per_frame(audio_format);
+
+    // Adding the stream will start the audio callbacks.
+    if (cras_client_add_stream(client_, &stream_id_, stream_params)) {
+      DLOG(WARNING) << "Failed to add the stream.";
+      callback_->OnError(this);
+      callback_ = NULL;
+    }
   }
 
   // Done with config params.
@@ -224,6 +236,18 @@ int CrasInputStream::SamplesReady(cras_client* client,
   return frames;
 }
 
+// Static callback asking for a single sample. Run on high priority thread.
+int CrasInputStream::HotwordSampleReady(cras_client* client,
+                                        cras_audio_format* fmt,
+                                        uint8* hotword_phrase,
+                                        size_t frames,
+                                        const timespec* sample_ts,
+                                        void* arg) {
+  CrasInputStream* me = static_cast<CrasInputStream*>(arg);
+  me->ReadAudio(frames, single_sample, sample_ts);
+  return frames;
+}
+
 // Static callback for stream errors.
 int CrasInputStream::StreamError(cras_client* client,
                                  cras_stream_id_t stream_id,