Letting Flash join MediaSession (stack implementaion)

content/browser/media/session/audio_focus_manager_unittest.cc

Index: content/browser/media/session/audio_focus_manager_unittest.cc
diff --git a/content/browser/media/session/audio_focus_manager_unittest.cc b/content/browser/media/session/audio_focus_manager_unittest.cc
index 11bf186aa837b9dd44b11cda8fdcd1bd7767eef4..df66e862491718d70a5045ba82c7fbe0b1a42ab9 100644
--- a/content/browser/media/session/audio_focus_manager_unittest.cc
+++ b/content/browser/media/session/audio_focus_manager_unittest.cc
@@ -4,14 +4,30 @@
 
 #include "content/browser/media/session/audio_focus_manager.h"
 
+#include "base/command_line.h"
 #include "content/browser/media/session/media_session.h"
+#include "content/browser/media/session/media_session_observer.h"
 #include "content/public/test/mock_render_process_host.h"
 #include "content/public/test/test_browser_context.h"
 #include "content/public/test/test_browser_thread.h"
 #include "content/test/test_web_contents.h"
+#include "media/base/media_content_type.h"
+#include "media/base/media_switches.h"
 
 namespace content {
 
+namespace {
+
+class MockMediaSessionObserver : public MediaSessionObserver {
+ public:
+  void OnSuspend(int player_id) override {}
+  void OnResume(int player_id) override {}
+  void OnSetVolumeMultiplier(
+      int player_id, double volume_multiplier) override {}
+};
+
+}  // anonymous namespace
+
 using AudioFocusType = AudioFocusManager::AudioFocusType;
 using SuspendType = MediaSession::SuspendType;
 
@@ -20,9 +36,12 @@ class AudioFocusManagerTest : public testing::Test {
   AudioFocusManagerTest() : ui_thread_(BrowserThread::UI, &message_loop_) {}
 
   void SetUp() override {
+    base::CommandLine::ForCurrentProcess()->AppendSwitch(
+        switches::kEnableDefaultMediaSession);
     rph_factory_.reset(new MockRenderProcessHostFactory());
     SiteInstanceImpl::set_render_process_host_factory(rph_factory_.get());
     browser_context_.reset(new TestBrowserContext());
+    pepper_observer_.reset(new MockMediaSessionObserver());
   }
 
   void TearDown() override {
@@ -31,25 +50,55 @@ class AudioFocusManagerTest : public testing::Test {
     rph_factory_.reset();
   }
 
-  WebContents* GetAudioFocusedContent() const {
-    if (!AudioFocusManager::GetInstance()->focus_entry_)
-      return nullptr;
-    return AudioFocusManager::GetInstance()->focus_entry_->web_contents();
+  MediaSession* GetAudioFocusedSession() const {
+    const auto& audio_focus_stack =
+        AudioFocusManager::GetInstance()->audio_focus_stack_;
+    for (auto iter = audio_focus_stack.rbegin();
+         iter != audio_focus_stack.rend(); ++iter) {
+      if ((*iter)->audio_focus_type() ==
+          AudioFocusManager::AudioFocusType::Gain)
+        return (*iter);
+    }
+    return nullptr;
   }
 
   int GetTransientMaybeDuckCount() const {
-    return AudioFocusManager::GetInstance()->TransientMayDuckEntriesCount();
+    int count = 0;
+    const auto& audio_focus_stack =
+        AudioFocusManager::GetInstance()->audio_focus_stack_;
+    for (auto iter = audio_focus_stack.rbegin();
+         iter != audio_focus_stack.rend(); ++iter) {
+      if ((*iter)->audio_focus_type() ==
+          AudioFocusManager::AudioFocusType::GainTransientMayDuck) {
+          ++count;
+      } else {
+        break;
+      }
+    }
+
+    return count;
   }
 
   double IsSessionDucking(MediaSession* session) {
     return session->is_ducking_;  // Quack! Quack!
   }
 
+  void RequestAudioFocus(MediaSession* session,
+                         AudioFocusManager::AudioFocusType audio_focus_type) {
+    session->RequestSystemAudioFocus(audio_focus_type);
+  }
+
+  void AbandonAudioFocus(MediaSession* session) {
+    session->AbandonSystemAudioFocusIfNeeded();
+  }
+
   WebContents* CreateWebContents() {
     return TestWebContents::Create(browser_context_.get(),
         SiteInstance::SiteInstance::Create(browser_context_.get()));
   }
 
+  std::unique_ptr<MediaSessionObserver> pepper_observer_;
+
  private:
   base::MessageLoopForUI message_loop_;
   TestBrowserThread ui_thread_;
@@ -74,48 +123,42 @@ TEST_F(AudioFocusManagerTest, RequestAudioFocusGain_ReplaceFocusedEntry) {
   std::unique_ptr<WebContents> web_contents_3(CreateWebContents());
   MediaSession* media_session_3 = MediaSession::Get(web_contents_3.get());
 
-  ASSERT_EQ(nullptr, GetAudioFocusedContent());
+  ASSERT_EQ(nullptr, GetAudioFocusedSession());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session_1, AudioFocusManager::AudioFocusType::Gain);
-  ASSERT_EQ(web_contents_1.get(), GetAudioFocusedContent());
+  RequestAudioFocus(media_session_1, AudioFocusManager::AudioFocusType::Gain);
+  ASSERT_EQ(media_session_1, GetAudioFocusedSession());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session_2, AudioFocusManager::AudioFocusType::Gain);
-  ASSERT_EQ(web_contents_2.get(), GetAudioFocusedContent());
+  RequestAudioFocus(media_session_2, AudioFocusManager::AudioFocusType::Gain);
+  ASSERT_EQ(media_session_2, GetAudioFocusedSession());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session_3, AudioFocusManager::AudioFocusType::Gain);
-  ASSERT_EQ(web_contents_3.get(), GetAudioFocusedContent());
+  RequestAudioFocus(media_session_3, AudioFocusManager::AudioFocusType::Gain);
+  ASSERT_EQ(media_session_3, GetAudioFocusedSession());
 }
 
 TEST_F(AudioFocusManagerTest, RequestAudioFocusGain_Duplicate) {
   std::unique_ptr<WebContents> web_contents(CreateWebContents());
   MediaSession* media_session = MediaSession::Get(web_contents.get());
 
-  ASSERT_EQ(nullptr, GetAudioFocusedContent());
+  ASSERT_EQ(nullptr, GetAudioFocusedSession());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session, AudioFocusManager::AudioFocusType::Gain);
-  ASSERT_EQ(web_contents.get(), GetAudioFocusedContent());
+  RequestAudioFocus(media_session, AudioFocusManager::AudioFocusType::Gain);
+  ASSERT_EQ(media_session, GetAudioFocusedSession());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session, AudioFocusManager::AudioFocusType::Gain);
-  ASSERT_EQ(web_contents.get(), GetAudioFocusedContent());
+  RequestAudioFocus(media_session, AudioFocusManager::AudioFocusType::Gain);
+  ASSERT_EQ(media_session, GetAudioFocusedSession());
 }
 
 TEST_F(AudioFocusManagerTest, RequestAudioFocusGain_FromTransient) {
   std::unique_ptr<WebContents> web_contents(CreateWebContents());
   MediaSession* media_session = MediaSession::Get(web_contents.get());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
+  RequestAudioFocus(
       media_session, AudioFocusManager::AudioFocusType::GainTransientMayDuck);
-  ASSERT_EQ(nullptr, GetAudioFocusedContent());
+  ASSERT_EQ(nullptr, GetAudioFocusedSession());
   ASSERT_EQ(1, GetTransientMaybeDuckCount());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session, AudioFocusManager::AudioFocusType::Gain);
-  ASSERT_EQ(web_contents.get(), GetAudioFocusedContent());
+  RequestAudioFocus(media_session, AudioFocusManager::AudioFocusType::Gain);
+  ASSERT_EQ(media_session, GetAudioFocusedSession());
   ASSERT_EQ(0, GetTransientMaybeDuckCount());
 }
 
@@ -123,14 +166,13 @@ TEST_F(AudioFocusManagerTest, RequestAudioFocusTransient_FromGain) {
   std::unique_ptr<WebContents> web_contents(CreateWebContents());
   MediaSession* media_session = MediaSession::Get(web_contents.get());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session, AudioFocusManager::AudioFocusType::Gain);
-  ASSERT_EQ(web_contents.get(), GetAudioFocusedContent());
+  RequestAudioFocus(media_session, AudioFocusManager::AudioFocusType::Gain);
+  ASSERT_EQ(media_session, GetAudioFocusedSession());
   ASSERT_EQ(0, GetTransientMaybeDuckCount());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
+  RequestAudioFocus(
       media_session, AudioFocusManager::AudioFocusType::GainTransientMayDuck);
-  ASSERT_EQ(nullptr, GetAudioFocusedContent());
+  ASSERT_EQ(nullptr, GetAudioFocusedSession());
   ASSERT_EQ(1, GetTransientMaybeDuckCount());
   ASSERT_FALSE(IsSessionDucking(media_session));
 }
@@ -142,17 +184,16 @@ TEST_F(AudioFocusManagerTest, RequestAudioFocusTransient_FromGainWhileDucking) {
   std::unique_ptr<WebContents> web_contents_2(CreateWebContents());
   MediaSession* media_session_2 = MediaSession::Get(web_contents_2.get());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session_1, AudioFocusManager::AudioFocusType::Gain);
+  RequestAudioFocus(media_session_1, AudioFocusManager::AudioFocusType::Gain);
   ASSERT_EQ(0, GetTransientMaybeDuckCount());
   ASSERT_FALSE(IsSessionDucking(media_session_1));
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
+  RequestAudioFocus(
       media_session_2, AudioFocusManager::AudioFocusType::GainTransientMayDuck);
   ASSERT_EQ(1, GetTransientMaybeDuckCount());
   ASSERT_TRUE(IsSessionDucking(media_session_1));
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
+  RequestAudioFocus(
       media_session_1, AudioFocusManager::AudioFocusType::GainTransientMayDuck);
   ASSERT_EQ(2, GetTransientMaybeDuckCount());
   ASSERT_FALSE(IsSessionDucking(media_session_1));
@@ -162,31 +203,30 @@ TEST_F(AudioFocusManagerTest, AbandonAudioFocus_RemovesFocusedEntry) {
   std::unique_ptr<WebContents> web_contents(CreateWebContents());
   MediaSession* media_session = MediaSession::Get(web_contents.get());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session, AudioFocusManager::AudioFocusType::Gain);
-  ASSERT_EQ(web_contents.get(), GetAudioFocusedContent());
+  RequestAudioFocus(media_session, AudioFocusManager::AudioFocusType::Gain);
+  ASSERT_EQ(media_session, GetAudioFocusedSession());
 
-  AudioFocusManager::GetInstance()->AbandonAudioFocus(media_session);
-  ASSERT_EQ(nullptr, GetAudioFocusedContent());
+  AbandonAudioFocus(media_session);
+  ASSERT_EQ(nullptr, GetAudioFocusedSession());
 }
 
 TEST_F(AudioFocusManagerTest, AbandonAudioFocus_NoAssociatedEntry) {
   std::unique_ptr<WebContents> web_contents(CreateWebContents());
   MediaSession* media_session = MediaSession::Get(web_contents.get());
 
-  AudioFocusManager::GetInstance()->AbandonAudioFocus(media_session);
-  ASSERT_EQ(nullptr, GetAudioFocusedContent());
+  AbandonAudioFocus(media_session);
+  ASSERT_EQ(nullptr, GetAudioFocusedSession());
 }
 
 TEST_F(AudioFocusManagerTest, AbandonAudioFocus_RemovesTransientEntry) {
   std::unique_ptr<WebContents> web_contents(CreateWebContents());
   MediaSession* media_session = MediaSession::Get(web_contents.get());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
+  RequestAudioFocus(
       media_session, AudioFocusManager::AudioFocusType::GainTransientMayDuck);
   ASSERT_EQ(1, GetTransientMaybeDuckCount());
 
-  AudioFocusManager::GetInstance()->AbandonAudioFocus(media_session);
+  AbandonAudioFocus(media_session);
   ASSERT_EQ(0, GetTransientMaybeDuckCount());
 }
 
@@ -197,24 +237,22 @@ TEST_F(AudioFocusManagerTest, AbandonAudioFocus_WhileDuckingThenResume) {
   std::unique_ptr<WebContents> web_contents_2(CreateWebContents());
   MediaSession* media_session_2 = MediaSession::Get(web_contents_2.get());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session_1, AudioFocusManager::AudioFocusType::Gain);
+  RequestAudioFocus(media_session_1, AudioFocusManager::AudioFocusType::Gain);
   ASSERT_EQ(0, GetTransientMaybeDuckCount());
   ASSERT_FALSE(IsSessionDucking(media_session_1));
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
+  RequestAudioFocus(
       media_session_2, AudioFocusManager::AudioFocusType::GainTransientMayDuck);
   ASSERT_EQ(1, GetTransientMaybeDuckCount());
   ASSERT_TRUE(IsSessionDucking(media_session_1));
 
-  AudioFocusManager::GetInstance()->AbandonAudioFocus(media_session_1);
+  AbandonAudioFocus(media_session_1);
   ASSERT_EQ(1, GetTransientMaybeDuckCount());
 
-  AudioFocusManager::GetInstance()->AbandonAudioFocus(media_session_2);
+  AbandonAudioFocus(media_session_2);
   ASSERT_EQ(0, GetTransientMaybeDuckCount());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session_1, AudioFocusManager::AudioFocusType::Gain);
+  RequestAudioFocus(media_session_1, AudioFocusManager::AudioFocusType::Gain);
   ASSERT_FALSE(IsSessionDucking(media_session_1));
 }
 
@@ -225,17 +263,16 @@ TEST_F(AudioFocusManagerTest, AbandonAudioFocus_StopsDucking) {
   std::unique_ptr<WebContents> web_contents_2(CreateWebContents());
   MediaSession* media_session_2 = MediaSession::Get(web_contents_2.get());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session_1, AudioFocusManager::AudioFocusType::Gain);
+  RequestAudioFocus(media_session_1, AudioFocusManager::AudioFocusType::Gain);
   ASSERT_EQ(0, GetTransientMaybeDuckCount());
   ASSERT_FALSE(IsSessionDucking(media_session_1));
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
+  RequestAudioFocus(
       media_session_2, AudioFocusManager::AudioFocusType::GainTransientMayDuck);
   ASSERT_EQ(1, GetTransientMaybeDuckCount());
   ASSERT_TRUE(IsSessionDucking(media_session_1));
 
-  AudioFocusManager::GetInstance()->AbandonAudioFocus(media_session_2);
+  AbandonAudioFocus(media_session_2);
   ASSERT_EQ(0, GetTransientMaybeDuckCount());
   ASSERT_FALSE(IsSessionDucking(media_session_1));
 }
@@ -247,28 +284,26 @@ TEST_F(AudioFocusManagerTest, DuckWhilePlaying) {
   std::unique_ptr<WebContents> web_contents_2(CreateWebContents());
   MediaSession* media_session_2 = MediaSession::Get(web_contents_2.get());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session_1, AudioFocusManager::AudioFocusType::Gain);
+  RequestAudioFocus(media_session_1, AudioFocusManager::AudioFocusType::Gain);
   ASSERT_FALSE(IsSessionDucking(media_session_1));
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
+  RequestAudioFocus(
       media_session_2, AudioFocusManager::AudioFocusType::GainTransientMayDuck);
   ASSERT_TRUE(IsSessionDucking(media_session_1));
 }
 
-TEST_F(AudioFocusManagerTest, DuckWhenStarting) {
+TEST_F(AudioFocusManagerTest, GainSuspendsTransient) {
   std::unique_ptr<WebContents> web_contents_1(CreateWebContents());
   MediaSession* media_session_1 = MediaSession::Get(web_contents_1.get());
 
   std::unique_ptr<WebContents> web_contents_2(CreateWebContents());
   MediaSession* media_session_2 = MediaSession::Get(web_contents_2.get());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
+  RequestAudioFocus(
       media_session_2, AudioFocusManager::AudioFocusType::GainTransientMayDuck);
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session_1, AudioFocusManager::AudioFocusType::Gain);
-  ASSERT_TRUE(IsSessionDucking(media_session_1));
+  RequestAudioFocus(media_session_1, AudioFocusManager::AudioFocusType::Gain);
+  ASSERT_TRUE(media_session_2->IsSuspended());
 }
 
 TEST_F(AudioFocusManagerTest, DuckWithMultipleTransients) {
@@ -281,22 +316,21 @@ TEST_F(AudioFocusManagerTest, DuckWithMultipleTransients) {
   std::unique_ptr<WebContents> web_contents_3(CreateWebContents());
   MediaSession* media_session_3 = MediaSession::Get(web_contents_3.get());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session_1, AudioFocusManager::AudioFocusType::Gain);
+  RequestAudioFocus(media_session_1, AudioFocusManager::AudioFocusType::Gain);
   ASSERT_FALSE(IsSessionDucking(media_session_1));
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
+  RequestAudioFocus(
       media_session_2, AudioFocusManager::AudioFocusType::GainTransientMayDuck);
   ASSERT_TRUE(IsSessionDucking(media_session_1));
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
+  RequestAudioFocus(
       media_session_3, AudioFocusManager::AudioFocusType::GainTransientMayDuck);
   ASSERT_TRUE(IsSessionDucking(media_session_1));
 
-  AudioFocusManager::GetInstance()->AbandonAudioFocus(media_session_2);
+  AbandonAudioFocus(media_session_2);
   ASSERT_TRUE(IsSessionDucking(media_session_1));
 
-  AudioFocusManager::GetInstance()->AbandonAudioFocus(media_session_3);
+  AbandonAudioFocus(media_session_3);
   ASSERT_FALSE(IsSessionDucking(media_session_1));
 }
 
@@ -304,19 +338,18 @@ TEST_F(AudioFocusManagerTest, WebContentsDestroyed_ReleasesFocus) {
   std::unique_ptr<WebContents> web_contents(CreateWebContents());
   MediaSession* media_session = MediaSession::Get(web_contents.get());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session, AudioFocusManager::AudioFocusType::Gain);
-  ASSERT_EQ(web_contents.get(), GetAudioFocusedContent());
+  RequestAudioFocus(media_session, AudioFocusManager::AudioFocusType::Gain);
+  ASSERT_EQ(media_session, GetAudioFocusedSession());
 
   web_contents.reset();
-  ASSERT_EQ(nullptr, GetAudioFocusedContent());
+  ASSERT_EQ(nullptr, GetAudioFocusedSession());
 }
 
 TEST_F(AudioFocusManagerTest, WebContentsDestroyed_ReleasesTransients) {
   std::unique_ptr<WebContents> web_contents(CreateWebContents());
   MediaSession* media_session = MediaSession::Get(web_contents.get());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
+  RequestAudioFocus(
       media_session, AudioFocusManager::AudioFocusType::GainTransientMayDuck);
   ASSERT_EQ(1, GetTransientMaybeDuckCount());
 
@@ -331,11 +364,10 @@ TEST_F(AudioFocusManagerTest, WebContentsDestroyed_StopsDucking) {
   std::unique_ptr<WebContents> web_contents_2(CreateWebContents());
   MediaSession* media_session_2 = MediaSession::Get(web_contents_2.get());
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
-      media_session_1, AudioFocusManager::AudioFocusType::Gain);
+  RequestAudioFocus(media_session_1, AudioFocusManager::AudioFocusType::Gain);
   ASSERT_FALSE(IsSessionDucking(media_session_1));
 
-  AudioFocusManager::GetInstance()->RequestAudioFocus(
+  RequestAudioFocus(
       media_session_2, AudioFocusManager::AudioFocusType::GainTransientMayDuck);
   ASSERT_TRUE(IsSessionDucking(media_session_1));
 
@@ -343,4 +375,61 @@ TEST_F(AudioFocusManagerTest, WebContentsDestroyed_StopsDucking) {
   ASSERT_FALSE(IsSessionDucking(media_session_1));
 }
 
+TEST_F(AudioFocusManagerTest, PepperRequestsGainFocus) {
+  std::unique_ptr<WebContents> web_contents(CreateWebContents());
+  MediaSession* media_session = MediaSession::Get(web_contents.get());
+
+  media_session->AddPlayer(
+      pepper_observer_.get(), 0, media::MediaContentType::Pepper);
+  ASSERT_EQ(media_session, GetAudioFocusedSession());
+
+  media_session->RemovePlayer(pepper_observer_.get(), 0);
+  ASSERT_EQ(nullptr, GetAudioFocusedSession());
+}
+
+TEST_F(AudioFocusManagerTest, GainDucksPepper) {
+  std::unique_ptr<WebContents> web_contents_1(CreateWebContents());
+  MediaSession* media_session_1 = MediaSession::Get(web_contents_1.get());
+
+  std::unique_ptr<WebContents> web_contents_2(CreateWebContents());
+  MediaSession* media_session_2 = MediaSession::Get(web_contents_2.get());
+
+  media_session_1->AddPlayer(
+      pepper_observer_.get(), 0, media::MediaContentType::Pepper);
+
+  RequestAudioFocus(
+      media_session_2, AudioFocusManager::AudioFocusType::Gain);
+
+  ASSERT_EQ(media_session_2, GetAudioFocusedSession());
+  ASSERT_TRUE(media_session_1->IsActive());
+  ASSERT_TRUE(IsSessionDucking(media_session_1));
+}
+
+TEST_F(AudioFocusManagerTest, AbandoningGainFocusRevokesTopMostPepperSession) {
+  std::unique_ptr<WebContents> web_contents_1(CreateWebContents());
+  MediaSession* media_session_1 = MediaSession::Get(web_contents_1.get());
+
+  std::unique_ptr<WebContents> web_contents_2(CreateWebContents());
+  MediaSession* media_session_2 = MediaSession::Get(web_contents_2.get());
+
+  std::unique_ptr<WebContents> web_contents_3(CreateWebContents());
+  MediaSession* media_session_3 = MediaSession::Get(web_contents_3.get());
+
+  media_session_1->AddPlayer(
+      pepper_observer_.get(), 0, media::MediaContentType::Pepper);
+
+  RequestAudioFocus(
+      media_session_2, AudioFocusManager::AudioFocusType::Gain);
+  RequestAudioFocus(
+      media_session_3, AudioFocusManager::AudioFocusType::Gain);
+
+  ASSERT_EQ(media_session_3, GetAudioFocusedSession());
+  ASSERT_TRUE(media_session_2->IsReallySuspended());
+  ASSERT_TRUE(media_session_1->IsActive());
+  ASSERT_TRUE(IsSessionDucking(media_session_1));
+
+  AbandonAudioFocus(media_session_3);
+  ASSERT_EQ(media_session_1, GetAudioFocusedSession());
+}
+
 }  // namespace content