CRAS: Handle metadata and position info from Media Session

Upon receiving the updated metadata and position information for the
active media session from Media Session Controller, cras_audio_handler
will parse and repack the data for the audio client for further
processing.

Categorize the MediaSessionInfo::SessionState::kDucking to "playing"
instead of "stopped" for audio client.

BUG=b:147365593, b:147365793, b:147367068
TEST=chromeos_unittests

Change-Id: Iea65b931580b5725b807ae268958cf225e121195
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2088799Reviewed-by: Becca Hughes <beccahughes@chromium.org>
Reviewed-by: Jenny Zhang <jennyz@chromium.org>
Commit-Queue: Michael Sun <michaelfsun@google.com>
Cr-Commit-Position: refs/heads/master@{#747438}

chromeos/audio/cras_audio_handler.cc

@@ -17,6 +17,7 @@
 #include "base/bind_helpers.h"
 #include "base/logging.h"
 #include "base/single_thread_task_runner.h"
+#include "base/strings/utf_string_conversions.h"
 #include "base/system/sys_info.h"
 #include "base/system/system_monitor.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ -243,12 +244,13 @@ void CrasAudioHandler::MediaSessionInfoChanged(
 
   switch (session_info->state) {
     case media_session::mojom::MediaSessionInfo::SessionState::kActive:
+    case media_session::mojom::MediaSessionInfo::SessionState::kDucking:
       state = "playing";
       break;
     case media_session::mojom::MediaSessionInfo::SessionState::kSuspended:
       state = "paused";
       break;
-    default:
+    case media_session::mojom::MediaSessionInfo::SessionState::kInactive:
       state = "stopped";
       break;
   }
@@ -256,6 +258,44 @@ void CrasAudioHandler::MediaSessionInfoChanged(
   CrasAudioClient::Get()->SetPlayerPlaybackStatus(state);
 }
 
+void CrasAudioHandler::MediaSessionMetadataChanged(
+    const base::Optional<media_session::MediaMetadata>& metadata) {
+  if (!metadata || metadata->IsEmpty())
+    return;
+
+  const std::map<std::string, std::string> metadata_map = {
+      {"title", base::UTF16ToASCII(metadata->title)},
+      {"artist", base::UTF16ToASCII(metadata->artist)},
+      {"album", base::UTF16ToASCII(metadata->album)}};
+  const std::string source_title = base::UTF16ToASCII(metadata->source_title);
+
+  // Assume media duration/length should always change with new metadata.
+  fetch_media_session_duration_ = true;
+  CrasAudioClient::Get()->SetPlayerMetadata(metadata_map);
+  CrasAudioClient::Get()->SetPlayerIdentity(source_title);
+}
+
+void CrasAudioHandler::MediaSessionPositionChanged(
+    const base::Optional<media_session::MediaPosition>& position) {
+  if (!position)
+    return;
+
+  int64_t duration = 0;
+  if (fetch_media_session_duration_) {
+    duration = position->duration().InMicroseconds();
+    if (duration > 0) {
+      CrasAudioClient::Get()->SetPlayerDuration(duration);
+      fetch_media_session_duration_ = false;
+    }
+  }
+
+  int64_t current_position = position->GetPosition().InMicroseconds();
+  if (current_position < 0 || current_position > duration)
+    return;
+
+  CrasAudioClient::Get()->SetPlayerPosition(current_position);
+}
+
 void CrasAudioHandler::AddAudioObserver(AudioObserver* observer) {
   observers_.AddObserver(observer);
 }

chromeos/audio/cras_audio_handler.h

@@ -139,14 +139,14 @@ class COMPONENT_EXPORT(CHROMEOS_AUDIO) CrasAudioHandler
   void MediaSessionInfoChanged(
       media_session::mojom::MediaSessionInfoPtr session_info) override;
   void MediaSessionMetadataChanged(
-      const base::Optional<media_session::MediaMetadata>& metadata) override {}
+      const base::Optional<media_session::MediaMetadata>& metadata) override;
   void MediaSessionActionsChanged(
       const std::vector<media_session::mojom::MediaSessionAction>& actions)
       override {}
   void MediaSessionChanged(
       const base::Optional<base::UnguessableToken>& request_id) override {}
   void MediaSessionPositionChanged(
-      const base::Optional<media_session::MediaPosition>& position) override {}
+      const base::Optional<media_session::MediaPosition>& position) override;
 
   // Adds an audio observer.
   void AddAudioObserver(AudioObserver* observer);
@@ -612,6 +612,8 @@ class COMPONENT_EXPORT(CHROMEOS_AUDIO) CrasAudioHandler
 
   int num_active_output_streams_ = 0;
 
+  bool fetch_media_session_duration_ = false;
+
   // Task runner of browser main thread. All member variables should be accessed
   // on this thread.
   scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;