CRAS: Add SetPlayerDuration Function to cras_audio_client

Add a new function in cras_audio_client to support propagate media
track duration/length to Chrome OS via DBUS CRAS Control Interface. As
Bluetooth Stack (BlueZ) and MPRIS defined media duration to be a part of
metadata, SetPlayerDuration function will wrap the duration informatio
into the metadata format and forward it to DBUS.

BUG=b:147365563
TEST=chromeos_unittests

Change-Id: I3a6b91247a58f8898fa05f0dfe89195cdbfe7c8c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2081262
Commit-Queue: Michael Sun <michaelfsun@google.com>
Reviewed-by: Jenny Zhang <jennyz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#746994}

chromeos/dbus/audio/cras_audio_client.cc

@@ -355,6 +355,25 @@ class CrasAudioClientImpl : public CrasAudioClient {
                             base::DoNothing());
   }
 
+  void SetPlayerDuration(const int64_t& duration) override {
+    dbus::MethodCall method_call(cras::kCrasControlInterface,
+                                 cras::kSetPlayerMetadata);
+    dbus::MessageWriter writer(&method_call);
+    dbus::MessageWriter array_writer(nullptr);
+    dbus::MessageWriter dict_entry_writer(nullptr);
+
+    writer.OpenArray("{sv}", &array_writer);
+    array_writer.OpenDictEntry(&dict_entry_writer);
+    dict_entry_writer.AppendString("length");
+    dict_entry_writer.AppendVariantOfInt64(duration);
+    array_writer.CloseContainer(&dict_entry_writer);
+    writer.CloseContainer(&array_writer);
+
+    cras_proxy_->CallMethod(&method_call,
+                            dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+                            base::DoNothing());
+  }
+
   void SetPlayerMetadata(
       const std::map<std::string, std::string>& metadata) override {
     dbus::MethodCall method_call(cras::kCrasControlInterface,

chromeos/dbus/audio/cras_audio_client.h

@@ -175,6 +175,9 @@ class COMPONENT_EXPORT(DBUS_AUDIO) CrasAudioClient {
   // Sets the current track position for the player in microseconds
   virtual void SetPlayerPosition(const int64_t& position) = 0;
 
+  // Sets the current track duration for the player in microseconds
+  virtual void SetPlayerDuration(const int64_t& duration) = 0;
+
   // Sets the current media metadata including Title, Album, and Artist.
   virtual void SetPlayerMetadata(
       const std::map<std::string, std::string>& metadata) = 0;

chromeos/dbus/audio/cras_audio_client_unittest.cc

@@ -203,6 +203,29 @@ void ExpectArrayOfDictOfStringAndVariantStringArguments(
   EXPECT_FALSE(reader->HasMoreData());
 }
 
+// Expect the reader to have an array of dictionary of string and variant
+// int64.
+void ExpectArrayOfDictOfStringAndVariantInt64Arguments(
+    const std::map<std::string, int64_t>& expected_dict,
+    dbus::MessageReader* reader) {
+  dbus::MessageReader array_reader(nullptr);
+  ASSERT_TRUE(reader->PopArray(&array_reader));
+
+  dbus::MessageReader dict_entry_reader(nullptr);
+  for (auto& entry : expected_dict) {
+    EXPECT_TRUE(array_reader.HasMoreData());
+    ASSERT_TRUE(array_reader.PopDictEntry(&dict_entry_reader));
+
+    std::string key;
+    int64_t value;
+    ASSERT_TRUE(dict_entry_reader.PopString(&key));
+    EXPECT_EQ(entry.first, key);
+    ASSERT_TRUE(dict_entry_reader.PopVariantOfInt64(&value));
+    EXPECT_EQ(entry.second, value);
+  }
+  EXPECT_FALSE(reader->HasMoreData());
+}
+
 void WriteNodesToResponse(const AudioNodeList& node_list,
                           dbus::MessageWriter* writer) {
   dbus::MessageWriter sub_writer(nullptr);
@@ -1197,6 +1220,25 @@ TEST_F(CrasAudioClientTest, SetPlayerPosition) {
   base::RunLoop().RunUntilIdle();
 }
 
+TEST_F(CrasAudioClientTest, SetPlayerDuration) {
+  const int64_t kDuration = 20200302;
+  const std::map<std::string, int64_t> kMetadata = {{"length", kDuration}};
+  // Create response.
+  std::unique_ptr<dbus::Response> response(dbus::Response::CreateEmpty());
+
+  // Set expectations.
+  PrepareForMethodCall(
+      cras::kSetPlayerMetadata,
+      base::BindRepeating(&ExpectArrayOfDictOfStringAndVariantInt64Arguments,
+                          kMetadata),
+      response.get());
+
+  // Call method.
+  client()->SetPlayerDuration(kDuration);
+  // Run the message loop.
+  base::RunLoop().RunUntilIdle();
+}
+
 TEST_F(CrasAudioClientTest, SetPlayerMetadata) {
   const std::string kTitle = "Chrome Metadata Title";
   const std::string kAlbum = "Chrome Metadata Album";

chromeos/dbus/audio/fake_cras_audio_client.cc

@@ -220,6 +220,8 @@ void FakeCrasAudioClient::SetPlayerIdentity(
 
 void FakeCrasAudioClient::SetPlayerPosition(const int64_t& position) {}
 
+void FakeCrasAudioClient::SetPlayerDuration(const int64_t& duration) {}
+
 void FakeCrasAudioClient::SetPlayerMetadata(
     const std::map<std::string, std::string>& metadata) {}
 

chromeos/dbus/audio/fake_cras_audio_client.h

@@ -54,6 +54,7 @@ class COMPONENT_EXPORT(DBUS_AUDIO) FakeCrasAudioClient
   void SetPlayerPlaybackStatus(const std::string& playback_status) override;
   void SetPlayerIdentity(const std::string& playback_identity) override;
   void SetPlayerPosition(const int64_t& position) override;
+  void SetPlayerDuration(const int64_t& duration) override;
   void SetPlayerMetadata(
       const std::map<std::string, std::string>& metadata) override;
   void WaitForServiceToBeAvailable(