diff --git a/ash/ambient/ui/media_string_view.cc b/ash/ambient/ui/media_string_view.cc
index c0d40882516e5b..4a87052ec61032 100644
--- a/ash/ambient/ui/media_string_view.cc
+++ b/ash/ambient/ui/media_string_view.cc
@@ -17,8 +17,8 @@
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "components/prefs/pref_service.h"
-#include "services/media_session/public/cpp/media_session_service.h"
 #include "services/media_session/public/mojom/media_session.mojom.h"
+#include "services/media_session/public/mojom/media_session_service.mojom.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/paint_recorder.h"
@@ -242,7 +242,7 @@ void MediaStringView::InitLayout() {
 }
 
 void MediaStringView::BindMediaControllerObserver() {
-  media_session::MediaSessionService* service =
+  media_session::mojom::MediaSessionService* service =
       Shell::Get()->shell_delegate()->GetMediaSessionService();
   // Service might be unavailable under some test environments.
   if (!service)
diff --git a/ash/login/ui/lock_screen_media_controls_view.cc b/ash/login/ui/lock_screen_media_controls_view.cc
index d377f0981cc14c..5a499d872b370d 100644
--- a/ash/login/ui/lock_screen_media_controls_view.cc
+++ b/ash/login/ui/lock_screen_media_controls_view.cc
@@ -396,7 +396,7 @@ LockScreenMediaControlsView::LockScreenMediaControlsView(
   SetArtwork(base::nullopt);
 
   // |service| can be null in tests.
-  media_session::MediaSessionService* service =
+  media_session::mojom::MediaSessionService* service =
       Shell::Get()->shell_delegate()->GetMediaSessionService();
   if (!service)
     return;
diff --git a/ash/media/media_controller_impl.cc b/ash/media/media_controller_impl.cc
index ae323a42be7ebe..fe8a670b91964b 100644
--- a/ash/media/media_controller_impl.cc
+++ b/ash/media/media_controller_impl.cc
@@ -361,7 +361,7 @@ MediaControllerImpl::GetMediaSessionController() {
   if (!Shell::HasInstance())
     return nullptr;
 
-  media_session::MediaSessionService* service =
+  media_session::mojom::MediaSessionService* service =
       Shell::Get()->shell_delegate()->GetMediaSessionService();
   if (!service)
     return nullptr;
diff --git a/ash/media/media_notification_controller_impl.cc b/ash/media/media_notification_controller_impl.cc
index 64d759e9985b79..5e5c0c55c0e91b 100644
--- a/ash/media/media_notification_controller_impl.cc
+++ b/ash/media/media_notification_controller_impl.cc
@@ -108,7 +108,7 @@ MediaNotificationControllerImpl::MediaNotificationControllerImpl()
   }
 
   // May be null in tests.
-  media_session::MediaSessionService* service =
+  media_session::mojom::MediaSessionService* service =
       Shell::Get()->shell_delegate()->GetMediaSessionService();
   if (!service)
     return;
diff --git a/ash/shell_delegate.cc b/ash/shell_delegate.cc
index 930023f51dc389..14d6a022036e1c 100644
--- a/ash/shell_delegate.cc
+++ b/ash/shell_delegate.cc
@@ -24,7 +24,8 @@ aura::Window* ShellDelegate::CreateBrowserForTabDrop(
   return nullptr;
 }
 
-media_session::MediaSessionService* ShellDelegate::GetMediaSessionService() {
+media_session::mojom::MediaSessionService*
+ShellDelegate::GetMediaSessionService() {
   return nullptr;
 }
 
diff --git a/ash/shell_delegate.h b/ash/shell_delegate.h
index 292e19cf558f30..84054219f4e1f1 100644
--- a/ash/shell_delegate.h
+++ b/ash/shell_delegate.h
@@ -15,7 +15,7 @@
 #include "mojo/public/cpp/bindings/pending_receiver.h"
 #include "services/device/public/mojom/bluetooth_system.mojom-forward.h"
 #include "services/device/public/mojom/fingerprint.mojom-forward.h"
-#include "services/media_session/public/cpp/media_session_service.h"
+#include "services/media_session/public/mojom/media_session_service.mojom-forward.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace aura {
@@ -104,7 +104,7 @@ class ASH_EXPORT ShellDelegate {
 
   // Returns an interface to the Media Session service, or null if not
   // available.
-  virtual media_session::MediaSessionService* GetMediaSessionService();
+  virtual media_session::mojom::MediaSessionService* GetMediaSessionService();
 
   virtual void OpenKeyboardShortcutHelpPage() const {}
 };
diff --git a/ash/system/media/unified_media_controls_controller.cc b/ash/system/media/unified_media_controls_controller.cc
index caf361a9b3fb7f..507cc804fd34da 100644
--- a/ash/system/media/unified_media_controls_controller.cc
+++ b/ash/system/media/unified_media_controls_controller.cc
@@ -34,7 +34,7 @@ constexpr base::TimeDelta kHideArtworkDelay =
 UnifiedMediaControlsController::UnifiedMediaControlsController(
     Delegate* delegate)
     : delegate_(delegate) {
-  media_session::MediaSessionService* service =
+  media_session::mojom::MediaSessionService* service =
       Shell::Get()->shell_delegate()->GetMediaSessionService();
   // Happens in test.
   if (!service)
diff --git a/chrome/browser/ui/ash/chrome_shell_delegate.cc b/chrome/browser/ui/ash/chrome_shell_delegate.cc
index bcd4aee9a0d229..84d1c742f7a345 100644
--- a/chrome/browser/ui/ash/chrome_shell_delegate.cc
+++ b/chrome/browser/ui/ash/chrome_shell_delegate.cc
@@ -180,7 +180,7 @@ void ChromeShellDelegate::BindMultiDeviceSetup(
     service->BindMultiDeviceSetup(std::move(receiver));
 }
 
-media_session::MediaSessionService*
+media_session::mojom::MediaSessionService*
 ChromeShellDelegate::GetMediaSessionService() {
   return &content::GetMediaSessionService();
 }
diff --git a/chrome/browser/ui/ash/chrome_shell_delegate.h b/chrome/browser/ui/ash/chrome_shell_delegate.h
index 73613eca4926b6..348c94ceb5093e 100644
--- a/chrome/browser/ui/ash/chrome_shell_delegate.h
+++ b/chrome/browser/ui/ash/chrome_shell_delegate.h
@@ -42,7 +42,7 @@ class ChromeShellDelegate : public ash::ShellDelegate {
       mojo::PendingReceiver<
           chromeos::multidevice_setup::mojom::MultiDeviceSetup> receiver)
       override;
-  media_session::MediaSessionService* GetMediaSessionService() override;
+  media_session::mojom::MediaSessionService* GetMediaSessionService() override;
   std::unique_ptr<ash::NearbyShareDelegate> CreateNearbyShareDelegate(
       ash::NearbyShareController* controller) const override;
 
diff --git a/content/browser/media/session/media_session_impl_unittest.cc b/content/browser/media/session/media_session_impl_unittest.cc
index 7f6ef30181fb6a..15573c26f08ea8 100644
--- a/content/browser/media/session/media_session_impl_unittest.cc
+++ b/content/browser/media/session/media_session_impl_unittest.cc
@@ -203,6 +203,9 @@ TEST_F(MediaSessionImplTest, SessionInfoState) {
     MockMediaSessionMojoObserver observer(*GetMediaSession());
     GetMediaSession()->StartDucking();
     observer.WaitForState(MediaSessionInfo::SessionState::kDucking);
+
+    EXPECT_TRUE(observer.session_info().Equals(
+        media_session::test::GetMediaSessionInfoSync(GetMediaSession())));
   }
 
   {
diff --git a/content/browser/media_session/media_session_service.cc b/content/browser/media_session/media_session_service.cc
index 6896ed9897c4eb..4d683e6bb1ec9e 100644
--- a/content/browser/media_session/media_session_service.cc
+++ b/content/browser/media_session/media_session_service.cc
@@ -9,16 +9,36 @@
 #include "base/threading/sequence_local_storage_slot.h"
 #include "content/public/browser/browser_thread.h"
 #include "mojo/public/cpp/bindings/remote.h"
-#include "services/media_session/media_session_service_impl.h"
+#include "services/media_session/media_session_service.h"
 #include "services/media_session/public/cpp/features.h"
 
 namespace content {
 
-media_session::MediaSessionService& GetMediaSessionService() {
+media_session::mojom::MediaSessionService& GetMediaSessionService() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
-  static base::NoDestructor<media_session::MediaSessionServiceImpl> service;
-  return *service;
+  // NOTE: We use sequence-local storage here strictly to limit the lifetime of
+  // this Remote to that of the UI-thread sequence. This ensures that it doesn't
+  // persist when the task environment is torn down and reinitialized e.g.
+  // between unit tests.
+  static base::NoDestructor<base::SequenceLocalStorageSlot<
+      mojo::Remote<media_session::mojom::MediaSessionService>>>
+      remote_slot;
+  auto& remote = remote_slot->GetOrCreateValue();
+  if (!remote) {
+    if (base::FeatureList::IsEnabled(
+            media_session::features::kMediaSessionService)) {
+      static base::NoDestructor<
+          std::unique_ptr<media_session::MediaSessionService>>
+          service;
+      *service = std::make_unique<media_session::MediaSessionService>(
+          remote.BindNewPipeAndPassReceiver());
+    } else {
+      // If the service is not enabled, bind to a disconnected pipe.
+      ignore_result(remote.BindNewPipeAndPassReceiver());
+    }
+  }
+  return *remote.get();
 }
 
 }  // namespace content
diff --git a/content/public/browser/media_session_service.h b/content/public/browser/media_session_service.h
index 15e7d34a84f712..75ddff3837814d 100644
--- a/content/public/browser/media_session_service.h
+++ b/content/public/browser/media_session_service.h
@@ -6,13 +6,14 @@
 #define CONTENT_PUBLIC_BROWSER_MEDIA_SESSION_SERVICE_H_
 
 #include "content/common/content_export.h"
-#include "services/media_session/public/cpp/media_session_service.h"
+#include "services/media_session/public/mojom/media_session_service.mojom.h"
 
 namespace content {
 
 // Returns the main control interface into the Media Session Service which runs
 // in the browser process.
-CONTENT_EXPORT media_session::MediaSessionService& GetMediaSessionService();
+CONTENT_EXPORT media_session::mojom::MediaSessionService&
+GetMediaSessionService();
 
 }  // namespace content
 
diff --git a/services/media_session/BUILD.gn b/services/media_session/BUILD.gn
index 9ee525f224f47e..a2aa38213d3eef 100644
--- a/services/media_session/BUILD.gn
+++ b/services/media_session/BUILD.gn
@@ -15,8 +15,8 @@ source_set("lib") {
     "audio_focus_request.h",
     "media_controller.cc",
     "media_controller.h",
-    "media_session_service_impl.cc",
-    "media_session_service_impl.h",
+    "media_session_service.cc",
+    "media_session_service.h",
   ]
 
   configs += [ "//build/config/compiler:wexit_time_destructors" ]
@@ -36,7 +36,7 @@ source_set("tests") {
   sources = [
     "audio_focus_manager_unittest.cc",
     "media_controller_unittest.cc",
-    "media_session_service_impl_unittest.cc",
+    "media_session_service_unittest.cc",
   ]
 
   deps = [
diff --git a/services/media_session/audio_focus_manager_unittest.cc b/services/media_session/audio_focus_manager_unittest.cc
index 4aa4125493e8fa..d2cc3173a11b64 100644
--- a/services/media_session/audio_focus_manager_unittest.cc
+++ b/services/media_session/audio_focus_manager_unittest.cc
@@ -17,11 +17,12 @@
 #include "build/chromeos_buildflags.h"
 #include "mojo/public/cpp/bindings/remote.h"
 #include "services/media_session/audio_focus_request.h"
-#include "services/media_session/media_session_service_impl.h"
+#include "services/media_session/media_session_service.h"
 #include "services/media_session/public/cpp/test/audio_focus_test_util.h"
 #include "services/media_session/public/cpp/test/mock_media_session.h"
 #include "services/media_session/public/mojom/audio_focus.mojom.h"
 #include "services/media_session/public/mojom/media_session.mojom.h"
+#include "services/media_session/public/mojom/media_session_service.mojom.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace media_session {
@@ -47,12 +48,13 @@ class AudioFocusManagerTest
     base::PowerMonitor::Initialize(std::move(power_source));
 
     // Create an instance of the MediaSessionService.
-    service_ = std::make_unique<MediaSessionServiceImpl>();
-    service_->BindAudioFocusManager(
+    service_ = std::make_unique<MediaSessionService>(
+        service_remote_.BindNewPipeAndPassReceiver());
+    service_remote_->BindAudioFocusManager(
         audio_focus_remote_.BindNewPipeAndPassReceiver());
-    service_->BindAudioFocusManagerDebug(
+    service_remote_->BindAudioFocusManagerDebug(
         audio_focus_debug_remote_.BindNewPipeAndPassReceiver());
-    service_->BindMediaControllerManager(
+    service_remote_->BindMediaControllerManager(
         controller_manager_remote_.BindNewPipeAndPassReceiver());
 
     audio_focus_remote_->SetEnforcementMode(GetParam());
@@ -64,6 +66,7 @@ class AudioFocusManagerTest
     base::RunLoop().RunUntilIdle();
 
     service_.reset();
+    service_remote_.reset();
     base::PowerMonitor::ShutdownForTesting();
   }
 
@@ -181,7 +184,7 @@ class AudioFocusManagerTest
 
   mojo::Remote<mojom::AudioFocusManager> CreateAudioFocusManagerRemote() {
     mojo::Remote<mojom::AudioFocusManager> remote;
-    service_->BindAudioFocusManager(remote.BindNewPipeAndPassReceiver());
+    service_remote_->BindAudioFocusManager(remote.BindNewPipeAndPassReceiver());
     return remote;
   }
 
@@ -279,7 +282,8 @@ class AudioFocusManagerTest
 
   base::test::TaskEnvironment task_environment_;
 
-  std::unique_ptr<MediaSessionServiceImpl> service_;
+  std::unique_ptr<MediaSessionService> service_;
+  mojo::Remote<mojom::MediaSessionService> service_remote_;
 
   mojo::Remote<mojom::AudioFocusManager> audio_focus_remote_;
   mojo::Remote<mojom::AudioFocusManagerDebug> audio_focus_debug_remote_;
diff --git a/services/media_session/media_controller_unittest.cc b/services/media_session/media_controller_unittest.cc
index 77b608d0a5c56c..164cd39745720d 100644
--- a/services/media_session/media_controller_unittest.cc
+++ b/services/media_session/media_controller_unittest.cc
@@ -14,12 +14,13 @@
 #include "base/time/time.h"
 #include "base/unguessable_token.h"
 #include "mojo/public/cpp/bindings/remote.h"
-#include "services/media_session/media_session_service_impl.h"
+#include "services/media_session/media_session_service.h"
 #include "services/media_session/public/cpp/media_metadata.h"
 #include "services/media_session/public/cpp/test/mock_media_session.h"
 #include "services/media_session/public/cpp/test/test_media_controller.h"
 #include "services/media_session/public/mojom/constants.mojom.h"
 #include "services/media_session/public/mojom/media_session.mojom.h"
+#include "services/media_session/public/mojom/media_session_service.mojom.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace media_session {
@@ -30,10 +31,11 @@ class MediaControllerTest : public testing::Test {
 
   void SetUp() override {
     // Create an instance of the MediaSessionService and bind some interfaces.
-    service_ = std::make_unique<MediaSessionServiceImpl>();
-    service_->BindAudioFocusManager(
+    service_ = std::make_unique<MediaSessionService>(
+        service_remote_.BindNewPipeAndPassReceiver());
+    service_remote_->BindAudioFocusManager(
         audio_focus_remote_.BindNewPipeAndPassReceiver());
-    service_->BindMediaControllerManager(
+    service_remote_->BindMediaControllerManager(
         controller_manager_remote_.BindNewPipeAndPassReceiver());
 
     controller_manager_remote_->CreateActiveMediaController(
@@ -70,6 +72,7 @@ class MediaControllerTest : public testing::Test {
  private:
   base::test::TaskEnvironment task_environment_;
   std::unique_ptr<MediaSessionService> service_;
+  mojo::Remote<mojom::MediaSessionService> service_remote_;
   mojo::Remote<mojom::AudioFocusManager> audio_focus_remote_;
   mojo::Remote<mojom::MediaController> media_controller_remote_;
   mojo::Remote<mojom::MediaControllerManager> controller_manager_remote_;
diff --git a/services/media_session/media_session_service_impl.cc b/services/media_session/media_session_service.cc
similarity index 60%
rename from services/media_session/media_session_service_impl.cc
rename to services/media_session/media_session_service.cc
index 27534e2cc1ad12..7672a8d0703b1d 100644
--- a/services/media_session/media_session_service_impl.cc
+++ b/services/media_session/media_session_service.cc
@@ -2,29 +2,31 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "services/media_session/media_session_service_impl.h"
+#include "services/media_session/media_session_service.h"
 
 #include "base/bind.h"
 #include "services/media_session/audio_focus_manager.h"
 
 namespace media_session {
 
-MediaSessionServiceImpl::MediaSessionServiceImpl()
-    : audio_focus_manager_(std::make_unique<AudioFocusManager>()) {}
+MediaSessionService::MediaSessionService(
+    mojo::PendingReceiver<mojom::MediaSessionService> receiver)
+    : receiver_(this, std::move(receiver)),
+      audio_focus_manager_(std::make_unique<AudioFocusManager>()) {}
 
-MediaSessionServiceImpl::~MediaSessionServiceImpl() = default;
+MediaSessionService::~MediaSessionService() = default;
 
-void MediaSessionServiceImpl::BindAudioFocusManager(
+void MediaSessionService::BindAudioFocusManager(
     mojo::PendingReceiver<mojom::AudioFocusManager> receiver) {
   audio_focus_manager_->BindToInterface(std::move(receiver));
 }
 
-void MediaSessionServiceImpl::BindAudioFocusManagerDebug(
+void MediaSessionService::BindAudioFocusManagerDebug(
     mojo::PendingReceiver<mojom::AudioFocusManagerDebug> receiver) {
   audio_focus_manager_->BindToDebugInterface(std::move(receiver));
 }
 
-void MediaSessionServiceImpl::BindMediaControllerManager(
+void MediaSessionService::BindMediaControllerManager(
     mojo::PendingReceiver<mojom::MediaControllerManager> receiver) {
   audio_focus_manager_->BindToControllerManagerInterface(std::move(receiver));
 }
diff --git a/services/media_session/media_session_service_impl.h b/services/media_session/media_session_service.h
similarity index 61%
rename from services/media_session/media_session_service_impl.h
rename to services/media_session/media_session_service.h
index c608ab181b1b99..947c92b2c34cda 100644
--- a/services/media_session/media_session_service_impl.h
+++ b/services/media_session/media_session_service.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef SERVICES_MEDIA_SESSION_MEDIA_SESSION_SERVICE_IMPL_H_
-#define SERVICES_MEDIA_SESSION_MEDIA_SESSION_SERVICE_IMPL_H_
+#ifndef SERVICES_MEDIA_SESSION_MEDIA_SESSION_SERVICE_H_
+#define SERVICES_MEDIA_SESSION_MEDIA_SESSION_SERVICE_H_
 
 #include <memory>
 #include <string>
@@ -11,20 +11,24 @@
 #include "base/macros.h"
 #include "mojo/public/cpp/bindings/pending_receiver.h"
 #include "mojo/public/cpp/bindings/receiver.h"
-#include "services/media_session/public/cpp/media_session_service.h"
+#include "services/media_session/public/mojom/media_session_service.mojom.h"
 
 namespace media_session {
 
 class AudioFocusManager;
 
-class MediaSessionServiceImpl : public MediaSessionService {
+class MediaSessionService : public mojom::MediaSessionService {
  public:
-  MediaSessionServiceImpl();
-  ~MediaSessionServiceImpl() override;
-  MediaSessionServiceImpl(const MediaSessionServiceImpl&) = delete;
-  MediaSessionServiceImpl& operator=(const MediaSessionServiceImpl&) = delete;
+  explicit MediaSessionService(
+      mojo::PendingReceiver<mojom::MediaSessionService> receiver);
+  ~MediaSessionService() override;
 
-  // MediaSessionService implementation:
+  const AudioFocusManager& audio_focus_manager_for_testing() const {
+    return *audio_focus_manager_.get();
+  }
+
+ private:
+  // mojom::MediaSessionService implementation:
   void BindAudioFocusManager(
       mojo::PendingReceiver<mojom::AudioFocusManager> receiver) override;
   void BindAudioFocusManagerDebug(
@@ -32,14 +36,12 @@ class MediaSessionServiceImpl : public MediaSessionService {
   void BindMediaControllerManager(
       mojo::PendingReceiver<mojom::MediaControllerManager> receiver) override;
 
-  const AudioFocusManager& audio_focus_manager_for_testing() const {
-    return *audio_focus_manager_.get();
-  }
-
- private:
+  mojo::Receiver<mojom::MediaSessionService> receiver_;
   std::unique_ptr<AudioFocusManager> audio_focus_manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(MediaSessionService);
 };
 
 }  // namespace media_session
 
-#endif  // SERVICES_MEDIA_SESSION_MEDIA_SESSION_SERVICE_IMPL_H_
+#endif  // SERVICES_MEDIA_SESSION_MEDIA_SESSION_SERVICE_H_
diff --git a/services/media_session/media_session_service_impl_unittest.cc b/services/media_session/media_session_service_unittest.cc
similarity index 52%
rename from services/media_session/media_session_service_impl_unittest.cc
rename to services/media_session/media_session_service_unittest.cc
index f889e7e44cdd0a..34c8597ecad095 100644
--- a/services/media_session/media_session_service_impl_unittest.cc
+++ b/services/media_session/media_session_service_unittest.cc
@@ -2,27 +2,28 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "services/media_session/media_session_service_impl.h"
+#include "services/media_session/media_session_service.h"
 
 #include "base/macros.h"
 #include "base/test/task_environment.h"
+#include "mojo/public/cpp/bindings/pending_receiver.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace media_session {
 
-class MediaSessionImplTest : public testing::Test {
+class MediaSessionTest : public testing::Test {
  public:
-  MediaSessionImplTest() = default;
-  ~MediaSessionImplTest() override = default;
+  MediaSessionTest() = default;
+  ~MediaSessionTest() override = default;
 
  private:
   base::test::TaskEnvironment task_environment_;
 
-  DISALLOW_COPY_AND_ASSIGN(MediaSessionImplTest);
+  DISALLOW_COPY_AND_ASSIGN(MediaSessionTest);
 };
 
-TEST_F(MediaSessionImplTest, InstantiateService) {
-  MediaSessionServiceImpl service;
+TEST_F(MediaSessionTest, InstantiateService) {
+  MediaSessionService service{mojo::NullReceiver()};
 }
 
 }  // namespace media_session
diff --git a/services/media_session/public/cpp/BUILD.gn b/services/media_session/public/cpp/BUILD.gn
index 93bdbb714c3b6e..e6801541378326 100644
--- a/services/media_session/public/cpp/BUILD.gn
+++ b/services/media_session/public/cpp/BUILD.gn
@@ -44,7 +44,6 @@ component("cpp") {
     "features.h",
     "media_image_manager.cc",
     "media_image_manager.h",
-    "media_session_service.h",
     "util.cc",
     "util.h",
   ]
diff --git a/services/media_session/public/cpp/media_session_service.h b/services/media_session/public/cpp/media_session_service.h
deleted file mode 100644
index d1ebc60a13f686..00000000000000
--- a/services/media_session/public/cpp/media_session_service.h
+++ /dev/null
@@ -1,36 +0,0 @@
-// Copyright 2020 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef SERVICES_MEDIA_SESSION_PUBLIC_CPP_MEDIA_SESSION_SERVICE_H_
-#define SERVICES_MEDIA_SESSION_PUBLIC_CPP_MEDIA_SESSION_SERVICE_H_
-
-#include <memory>
-
-#include "base/component_export.h"
-#include "mojo/public/cpp/bindings/pending_receiver.h"
-#include "services/media_session/public/mojom/audio_focus.mojom.h"
-#include "services/media_session/public/mojom/media_controller.mojom.h"
-
-namespace media_session {
-
-class AudioFocusManager;
-
-class COMPONENT_EXPORT(MEDIA_SESSION_CPP) MediaSessionService {
- public:
-  virtual ~MediaSessionService() = default;
-
-  virtual void BindAudioFocusManager(
-      mojo::PendingReceiver<mojom::AudioFocusManager> receiver) = 0;
-  virtual void BindAudioFocusManagerDebug(
-      mojo::PendingReceiver<mojom::AudioFocusManagerDebug> receiver) = 0;
-  virtual void BindMediaControllerManager(
-      mojo::PendingReceiver<mojom::MediaControllerManager> receiver) = 0;
-
- protected:
-  MediaSessionService() = default;
-};
-
-}  // namespace media_session
-
-#endif  // SERVICES_MEDIA_SESSION_PUBLIC_CPP_MEDIA_SESSION_SERVICE_H_
diff --git a/services/media_session/public/mojom/BUILD.gn b/services/media_session/public/mojom/BUILD.gn
index 00f77dd120b39a..4ee7adcc43eef1 100644
--- a/services/media_session/public/mojom/BUILD.gn
+++ b/services/media_session/public/mojom/BUILD.gn
@@ -11,6 +11,7 @@ mojom("mojom") {
     "constants.mojom",
     "media_controller.mojom",
     "media_session.mojom",
+    "media_session_service.mojom",
   ]
 
   public_deps = [
diff --git a/services/media_session/public/mojom/media_session_service.mojom b/services/media_session/public/mojom/media_session_service.mojom
new file mode 100644
index 00000000000000..977340211c46e7
--- /dev/null
+++ b/services/media_session/public/mojom/media_session_service.mojom
@@ -0,0 +1,21 @@
+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+module media_session.mojom;
+
+import "services/media_session/public/mojom/audio_focus.mojom";
+import "services/media_session/public/mojom/media_controller.mojom";
+
+// The main interface to the Media Session service. Privileged and bound only by
+// the browser process.
+interface MediaSessionService {
+  // Binds an AudioFocusManager endpoint in the service.
+  BindAudioFocusManager(pending_receiver<AudioFocusManager> receiver);
+
+  // Binds an endpoint for debugging the AudioFocusManager.
+  BindAudioFocusManagerDebug(pending_receiver<AudioFocusManagerDebug> receiver);
+
+  // Binds a MediaControllerManager endpoint in the service.
+  BindMediaControllerManager(pending_receiver<MediaControllerManager> receiver);
+};