[Media Session] Move switches to service

Move the media session and audio focus related switches to
the media session service.

BUG=875004

Change-Id: I54dad1eb47ac6288895ea3cac3824b181080f3e3
Reviewed-on: https://chromium-review.googlesource.com/1188747Reviewed-by: Stephen Lanham <slan@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Becca Hughes <beccahughes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#587676}

chrome/browser/DEPS

@@ -60,6 +60,7 @@ include_rules = [
   "+services/data_decoder/public",
   "+services/device/public",
   "+services/identity/public",
+  "+services/media_session/public",
   "+services/metrics/metrics_mojo_service.h",
   "+services/metrics/public",
   "+services/network/ignore_errors_cert_verifier.h",

chrome/browser/about_flags.cc

@@ -122,6 +122,7 @@
 #include "ppapi/buildflags/buildflags.h"
 #include "printing/buildflags/buildflags.h"
 #include "services/device/public/cpp/device_features.h"
+#include "services/media_session/public/cpp/switches.h"
 #include "services/network/public/cpp/features.h"
 #include "services/network/public/cpp/network_switches.h"
 #include "services/resource_coordinator/public/cpp/resource_coordinator_features.h"
@@ -775,11 +776,12 @@ const FeatureEntry::Choice kTLS13VariantChoices[] = {
 #if !defined(OS_ANDROID)
 const FeatureEntry::Choice kEnableAudioFocusChoices[] = {
     {flag_descriptions::kEnableAudioFocusDisabled, "", ""},
-    {flag_descriptions::kEnableAudioFocusEnabled, switches::kEnableAudioFocus,
-     ""},
+    {flag_descriptions::kEnableAudioFocusEnabled,
+     media_session::switches::kEnableAudioFocus, ""},
 #if BUILDFLAG(ENABLE_PLUGINS)
     {flag_descriptions::kEnableAudioFocusEnabledDuckFlash,
-     switches::kEnableAudioFocus, switches::kEnableAudioFocusDuckFlash},
+     media_session::switches::kEnableAudioFocus,
+     media_session::switches::kEnableAudioFocusDuckFlash},
 #endif  // BUILDFLAG(ENABLE_PLUGINS)
 };
 #endif  // !defined(OS_ANDROID)

chrome/browser/chromeos/accessibility/accessibility_manager.cc

@@ -78,7 +78,7 @@
 #include "extensions/common/host_id.h"
 #include "mash/public/mojom/launchable.mojom.h"
 #include "media/audio/sounds/sounds_manager.h"
-#include "media/base/media_switches.h"
+#include "services/media_session/public/cpp/switches.h"
 #include "services/service_manager/public/cpp/connector.h"
 #include "ui/accessibility/ax_enum_util.h"
 #include "ui/base/ime/chromeos/extension_ime_util.h"
@@ -1244,9 +1244,9 @@ void AccessibilityManager::PostLoadChromeVox() {
   }
 
   if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
-          ::switches::kEnableAudioFocus)) {
+          media_session::switches::kEnableAudioFocus)) {
     base::CommandLine::ForCurrentProcess()->AppendSwitch(
-        ::switches::kEnableAudioFocus);
+        media_session::switches::kEnableAudioFocus);
   }
 }
 

chromecast/browser/DEPS

@@ -37,6 +37,7 @@ include_rules = [
   "+media/mojo",
   "+mojo/public",
   "+net",
+  "+services/media_session/public",
   "+services/network/public/cpp",
   "+services/service_manager/public",
   "+services/service_manager/embedder",

chromecast/browser/cast_browser_main_parts.cc

@@ -64,6 +64,7 @@
 #include "gpu/command_buffer/service/gpu_switches.h"
 #include "media/base/media.h"
 #include "media/base/media_switches.h"
+#include "services/media_session/public/cpp/switches.h"
 #include "services/network/public/cpp/shared_url_loader_factory.h"
 #include "ui/base/ui_base_switches.h"
 #include "ui/compositor/compositor_switches.h"
@@ -231,7 +232,7 @@ const DefaultCommandLineSwitch kDefaultSwitches[] = {
     // GPU shader disk cache disabling is largely to conserve disk space.
     {switches::kDisableGpuShaderDiskCache, ""},
     // Enable media sessions by default (even on non-Android platforms).
-    {switches::kEnableInternalMediaSession, ""},
+    {media_session::switches::kEnableInternalMediaSession, ""},
 #endif
 #if BUILDFLAG(IS_CAST_AUDIO_ONLY)
     {switches::kDisableGpu, ""},

content/browser/BUILD.gn

@@ -138,6 +138,7 @@ jumbo_source_set("browser") {
     "//services/device/public/mojom:generic_sensor",
     "//services/file:lib",
     "//services/file/public/mojom",
+    "//services/media_session/public/cpp",
     "//services/media_session/public/mojom",
     "//services/metrics",
     "//services/metrics/public/cpp:metrics_cpp",

content/browser/media/media_internals_unittest.cc

@@ -25,6 +25,7 @@
 #include "media/base/channel_layout.h"
 #include "media/base/media_log.h"
 #include "media/base/media_switches.h"
+#include "services/media_session/public/cpp/switches.h"
 #include "services/media_session/public/mojom/audio_focus.mojom.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -309,7 +310,7 @@ class MediaInternalsAudioFocusTest : public testing::Test,
                             base::Unretained(this));
 
     scoped_command_line_.GetProcessCommandLine()->AppendSwitch(
-        switches::kEnableAudioFocus);
+        media_session::switches::kEnableAudioFocus);
 
     content::MediaInternals::GetInstance()->AddUpdateCallback(update_cb_);
     browser_context_.reset(new TestBrowserContext());

content/browser/media/session/audio_focus_delegate_default.cc

@@ -4,9 +4,8 @@
 
 #include "content/browser/media/session/audio_focus_delegate.h"
 
-#include "base/command_line.h"
 #include "content/browser/media/session/audio_focus_manager.h"
-#include "media/base/media_switches.h"
+#include "services/media_session/public/cpp/switches.h"
 #include "services/media_session/public/mojom/audio_focus.mojom.h"
 
 namespace content {
@@ -35,11 +34,6 @@ class AudioFocusDelegateDefault : public AudioFocusDelegate {
   AudioFocusType audio_focus_type_if_disabled_;
 };
 
-bool IsAudioFocusEnabled() {
-  return base::CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kEnableAudioFocus);
-}
-
 }  // anonymous namespace
 
 AudioFocusDelegateDefault::AudioFocusDelegateDefault(
@@ -52,7 +46,7 @@ bool AudioFocusDelegateDefault::RequestAudioFocus(
     AudioFocusType audio_focus_type) {
   audio_focus_type_if_disabled_ = audio_focus_type;
 
-  if (!IsAudioFocusEnabled())
+  if (!media_session::IsAudioFocusEnabled())
     return true;
 
   AudioFocusManager::GetInstance()->RequestAudioFocus(media_session_,
@@ -65,7 +59,7 @@ void AudioFocusDelegateDefault::AbandonAudioFocus() {
 }
 
 AudioFocusType AudioFocusDelegateDefault::GetCurrentFocusType() const {
-  if (IsAudioFocusEnabled()) {
+  if (media_session::IsAudioFocusEnabled()) {
     return AudioFocusManager::GetInstance()->GetFocusTypeForSession(
         media_session_);
   }

content/browser/media/session/audio_focus_delegate_default_browsertest.cc

@@ -8,14 +8,14 @@
 #include "content/public/test/content_browser_test.h"
 #include "content/shell/browser/shell.h"
 #include "media/base/media_content_type.h"
-#include "media/base/media_switches.h"
+#include "services/media_session/public/cpp/switches.h"
 
 namespace content {
 
 class AudioFocusDelegateDefaultBrowserTest : public ContentBrowserTest {
  protected:
   void SetUpCommandLine(base::CommandLine* command_line) override {
-    command_line->AppendSwitch(switches::kEnableAudioFocus);
+    command_line->AppendSwitch(media_session::switches::kEnableAudioFocus);
   }
 
   void Run(WebContents* start_contents, WebContents* interrupt_contents) {

content/browser/media/session/audio_focus_manager_unittest.cc

@@ -17,7 +17,7 @@
 #include "content/public/test/test_browser_thread_bundle.h"
 #include "content/test/test_web_contents.h"
 #include "media/base/media_content_type.h"
-#include "media/base/media_switches.h"
+#include "services/media_session/public/cpp/switches.h"
 #include "services/media_session/public/mojom/audio_focus.mojom.h"
 
 namespace content {
@@ -68,7 +68,7 @@ class AudioFocusManagerTest : public testing::Test {
 
   void SetUp() override {
     base::CommandLine::ForCurrentProcess()->AppendSwitch(
-        switches::kEnableAudioFocus);
+        media_session::switches::kEnableAudioFocus);
     rph_factory_.reset(new MockRenderProcessHostFactory());
     RenderProcessHostImpl::set_render_process_host_factory_for_testing(
         rph_factory_.get());

content/browser/media/session/media_session_browsertest.cc

@@ -15,6 +15,7 @@
 #include "content/public/test/content_browser_test_utils.h"
 #include "content/shell/browser/shell.h"
 #include "media/base/media_switches.h"
+#include "services/media_session/public/cpp/switches.h"
 
 namespace content {
 
@@ -36,7 +37,7 @@ class MediaSessionBrowserTest : public ContentBrowserTest {
   void EnableInternalMediaSesion() {
 #if !defined(OS_ANDROID)
     base::CommandLine::ForCurrentProcess()->AppendSwitch(
-        switches::kEnableInternalMediaSession);
+        media_session::switches::kEnableInternalMediaSession);
 #endif  // !defined(OS_ANDROID)
   }
 

content/browser/media/session/media_session_controllers_manager.cc

@@ -4,28 +4,11 @@
 
 #include "content/browser/media/session/media_session_controllers_manager.h"
 
-#include "base/command_line.h"
 #include "content/browser/media/session/media_session_controller.h"
-#include "media/base/media_switches.h"
+#include "services/media_session/public/cpp/switches.h"
 
 namespace content {
 
-namespace {
-
-bool IsMediaSessionEnabled() {
-// Media session is enabled on Android and Chrome OS to allow control of media
-// players as needed.
-#if defined(OS_ANDROID) || defined(OS_CHROMEOS)
-  return true;
-#else
-  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
-  return command_line->HasSwitch(switches::kEnableInternalMediaSession) ||
-         command_line->HasSwitch(switches::kEnableAudioFocus);
-#endif
-}
-
-}  // anonymous namespace
-
 MediaSessionControllersManager::MediaSessionControllersManager(
     MediaWebContentsObserver* media_web_contents_observer)
     : media_web_contents_observer_(media_web_contents_observer) {}
@@ -34,7 +17,7 @@ MediaSessionControllersManager::~MediaSessionControllersManager() = default;
 
 void MediaSessionControllersManager::RenderFrameDeleted(
     RenderFrameHost* render_frame_host) {
-  if (!IsMediaSessionEnabled())
+  if (!media_session::IsMediaSessionEnabled())
     return;
 
   for (auto it = controllers_map_.begin(); it != controllers_map_.end();) {
@@ -50,7 +33,7 @@ bool MediaSessionControllersManager::RequestPlay(
     bool has_audio,
     bool is_remote,
     media::MediaContentType media_content_type) {
-  if (!IsMediaSessionEnabled())
+  if (!media_session::IsMediaSessionEnabled())
     return true;
 
   // Since we don't remove session instances on pause, there may be an existing
@@ -78,7 +61,7 @@ bool MediaSessionControllersManager::RequestPlay(
 }
 
 void MediaSessionControllersManager::OnPause(const MediaPlayerId& id) {
-  if (!IsMediaSessionEnabled())
+  if (!media_session::IsMediaSessionEnabled())
     return;
 
   auto it = controllers_map_.find(id);
@@ -89,13 +72,13 @@ void MediaSessionControllersManager::OnPause(const MediaPlayerId& id) {
 }
 
 void MediaSessionControllersManager::OnEnd(const MediaPlayerId& id) {
-  if (!IsMediaSessionEnabled())
+  if (!media_session::IsMediaSessionEnabled())
     return;
   controllers_map_.erase(id);
 }
 
 void MediaSessionControllersManager::WebContentsMutedStateChanged(bool muted) {
-  if (!IsMediaSessionEnabled())
+  if (!media_session::IsMediaSessionEnabled())
     return;
 
   for (auto& entry : controllers_map_)

content/browser/media/session/media_session_controllers_manager_unittest.cc

@@ -10,7 +10,7 @@
 #include "content/test/test_render_view_host.h"
 #include "content/test/test_web_contents.h"
 #include "media/base/media_content_type.h"
-#include "media/base/media_switches.h"
+#include "services/media_session/public/cpp/switches.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -46,11 +46,11 @@ class MediaSessionControllersManagerTest
 #if !defined(OS_ANDROID)
     if (IsInternalMediaSessionEnabled()) {
       base::CommandLine::ForCurrentProcess()->AppendSwitch(
-          switches::kEnableInternalMediaSession);
+          media_session::switches::kEnableInternalMediaSession);
     }
     if (IsAudioFocusEnabled()) {
       base::CommandLine::ForCurrentProcess()->AppendSwitch(
-          switches::kEnableAudioFocus);
+          media_session::switches::kEnableAudioFocus);
     }
 #endif
 

content/browser/media/session/media_session_impl_visibility_browsertest.cc

@@ -20,6 +20,7 @@
 #include "content/public/test/test_navigation_observer.h"
 #include "content/shell/browser/shell.h"
 #include "media/base/media_switches.h"
+#include "services/media_session/public/cpp/switches.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace content {
@@ -107,7 +108,7 @@ class MediaSessionImplVisibilityBrowserTest
         switches::kAutoplayPolicy,
         switches::autoplay::kNoUserGestureRequiredPolicy);
 #if !defined(OS_ANDROID)
-    command_line->AppendSwitch(switches::kEnableAudioFocus);
+    command_line->AppendSwitch(media_session::switches::kEnableAudioFocus);
 #endif  // !defined(OS_ANDROID)
 
     VisibilityTestData params = GetVisibilityTestData();

content/browser/media/session/pepper_playback_observer.cc

@@ -11,7 +11,7 @@
 #include "content/common/frame_messages.h"
 #include "ipc/ipc_message_macros.h"
 #include "media/base/media_content_type.h"
-#include "media/base/media_switches.h"
+#include "services/media_session/public/cpp/switches.h"
 
 namespace content {
 
@@ -75,8 +75,9 @@ void PepperPlaybackObserver::PepperStartsPlayback(
 
   MediaSessionImpl::Get(contents_)->AddPlayer(
       players_map_[id].get(), PepperPlayerDelegate::kPlayerId,
-      media::IsAudioFocusDuckFlashEnabled() ? media::MediaContentType::Pepper
-                                            : media::MediaContentType::OneShot);
+      media_session::IsAudioFocusDuckFlashEnabled()
+          ? media::MediaContentType::Pepper
+          : media::MediaContentType::OneShot);
 }
 
 void PepperPlaybackObserver::PepperStopsPlayback(

content/browser/media/session/pepper_player_delegate.cc

@@ -8,7 +8,7 @@
 #include "content/browser/frame_host/render_frame_host_impl.h"
 #include "content/browser/media/session/pepper_playback_observer.h"
 #include "content/common/frame_messages.h"
-#include "media/base/media_switches.h"
+#include "services/media_session/public/cpp/switches.h"
 
 namespace content {
 
@@ -28,7 +28,7 @@ PepperPlayerDelegate::PepperPlayerDelegate(
 PepperPlayerDelegate::~PepperPlayerDelegate() = default;
 
 void PepperPlayerDelegate::OnSuspend(int player_id) {
-  if (!media::IsAudioFocusDuckFlashEnabled())
+  if (!media_session::IsAudioFocusDuckFlashEnabled())
     return;
 
   // Pepper player cannot be really suspended. Duck the volume instead.
@@ -37,7 +37,7 @@ void PepperPlayerDelegate::OnSuspend(int player_id) {
 }
 
 void PepperPlayerDelegate::OnResume(int player_id) {
-  if (!media::IsAudioFocusDuckFlashEnabled())
+  if (!media_session::IsAudioFocusDuckFlashEnabled())
     return;
 
   DCHECK_EQ(player_id, kPlayerId);
@@ -56,7 +56,7 @@ void PepperPlayerDelegate::OnSeekBackward(int player_id,
 
 void PepperPlayerDelegate::OnSetVolumeMultiplier(int player_id,
                                                  double volume_multiplier) {
-  if (!media::IsAudioFocusDuckFlashEnabled())
+  if (!media_session::IsAudioFocusDuckFlashEnabled())
     return;
 
   DCHECK_EQ(player_id, kPlayerId);

content/public/browser/BUILD.gn

@@ -340,6 +340,7 @@ jumbo_source_set("browser_sources") {
     "//media/mojo/interfaces:remoting",
     "//mojo/public/cpp/bindings",
     "//mojo/public/cpp/system",
+    "//services/media_session/public/cpp",
     "//services/media_session/public/mojom",
     "//services/network/public/mojom",
     "//services/resource_coordinator/public/cpp:resource_coordinator_cpp",

media/base/media_switches.cc

@@ -81,15 +81,6 @@ const char kUseCras[] = "use-cras";
 const char kUnsafelyAllowProtectedMediaIdentifierForDomain[] =
     "unsafely-allow-protected-media-identifier-for-domain";
 
-// Enable a internal audio focus management between tabs in such a way that two
-// tabs can't  play on top of each other.
-// The allowed values are: "" (empty) or |kEnableAudioFocusDuckFlash|.
-const char kEnableAudioFocus[] = "enable-audio-focus";
-
-// This value is used as an option for |kEnableAudioFocus|. Flash will
-// be ducked when losing audio focus.
-const char kEnableAudioFocusDuckFlash[] = "duck-flash";
-
 #if BUILDFLAG(ENABLE_RUNTIME_MEDIA_RENDERER_SELECTION)
 // Rather than use the renderer hosted remotely in the media service, fall back
 // to the default renderer within content_renderer. Does not change the behavior
@@ -181,12 +172,6 @@ const char kOverrideEnabledCdmInterfaceVersion[] =
 const char kOverrideHardwareSecureCodecsForTesting[] =
     "override-hardware-secure-codecs-for-testing";
 
-#if !defined(OS_ANDROID)
-// Turns on the internal media session backend. This should be used by embedders
-// that want to control the media playback with the media session interfaces.
-const char kEnableInternalMediaSession[] = "enable-internal-media-session";
-#endif  // !defined(OS_ANDROID)
-
 namespace autoplay {
 
 // Autoplay policy that requires a document user activation.
@@ -431,12 +416,6 @@ std::string GetEffectiveAutoplayPolicy(const base::CommandLine& command_line) {
 #endif
 }
 
-MEDIA_EXPORT bool IsAudioFocusDuckFlashEnabled() {
-  return base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
-             switches::kEnableAudioFocus) ==
-         switches::kEnableAudioFocusDuckFlash;
-}
-
 // Adds icons to the overflow menu on the native media controls.
 const base::Feature kOverflowIconsForMediaControls{
     "OverflowIconsForMediaControls", base::FEATURE_ENABLED_BY_DEFAULT};

media/base/media_switches.h

@@ -56,9 +56,6 @@ MEDIA_EXPORT extern const char kUseCras[];
 MEDIA_EXPORT extern const char
     kUnsafelyAllowProtectedMediaIdentifierForDomain[];
 
-MEDIA_EXPORT extern const char kEnableAudioFocus[];
-MEDIA_EXPORT extern const char kEnableAudioFocusDuckFlash[];
-
 #if BUILDFLAG(ENABLE_RUNTIME_MEDIA_RENDERER_SELECTION)
 MEDIA_EXPORT extern const char kDisableMojoRenderer[];
 #endif  // BUILDFLAG(ENABLE_RUNTIME_MEDIA_RENDERER_SELECTION)
@@ -85,10 +82,6 @@ MEDIA_EXPORT extern const char kClearKeyCdmPathForTesting[];
 MEDIA_EXPORT extern const char kOverrideEnabledCdmInterfaceVersion[];
 MEDIA_EXPORT extern const char kOverrideHardwareSecureCodecsForTesting[];
 
-#if !defined(OS_ANDROID)
-MEDIA_EXPORT extern const char kEnableInternalMediaSession[];
-#endif  // !defined(OS_ANDROID)
-
 namespace autoplay {
 
 MEDIA_EXPORT extern const char kDocumentUserActivationRequiredPolicy[];
@@ -165,10 +158,6 @@ MEDIA_EXPORT extern const base::Feature kDirectShowGetPhotoState;
 MEDIA_EXPORT std::string GetEffectiveAutoplayPolicy(
     const base::CommandLine& command_line);
 
-// Based on the command line of the current process, determine if
-// audio focus duck flash should be enabled.
-MEDIA_EXPORT bool IsAudioFocusDuckFlashEnabled();
-
 MEDIA_EXPORT bool IsVideoCaptureAcceleratedJpegDecodingEnabled();
 
 }  // namespace media

services/media_session/public/cpp/BUILD.gn

+# 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.
+
+component("cpp") {
+  output_name = "media_session_cpp"
+
+  sources = [
+    "switches.cc",
+    "switches.h",
+  ]
+
+  deps = [
+    "//base",
+  ]
+
+  defines = [ "IS_MEDIA_SESSION_CPP_IMPL" ]
+}

services/media_session/public/cpp/switches.cc

+// 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.
+
+#include "services/media_session/public/cpp/switches.h"
+
+#include "base/command_line.h"
+#include "build/build_config.h"
+
+namespace media_session {
+namespace switches {
+
+// Enable a internal audio focus management between tabs in such a way that two
+// tabs can't  play on top of each other.
+// The allowed values are: "" (empty) or |switches::kEnableAudioFocusDuckFlash|.
+const char kEnableAudioFocus[] = "enable-audio-focus";
+
+// This value is used as an option for |kEnableAudioFocus|. Flash will
+// be ducked when losing audio focus.
+const char kEnableAudioFocusDuckFlash[] = "duck-flash";
+
+#if !defined(OS_ANDROID)
+// Turns on the internal media session backend. This should be used by embedders
+// that want to control the media playback with the media session interfaces.
+const char kEnableInternalMediaSession[] = "enable-internal-media-session";
+#endif  // !defined(OS_ANDROID)
+
+}  // namespace switches
+
+bool IsAudioFocusEnabled() {
+  return base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableAudioFocus);
+}
+
+bool IsAudioFocusDuckFlashEnabled() {
+  return base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
+             switches::kEnableAudioFocus) ==
+         switches::kEnableAudioFocusDuckFlash;
+}
+
+bool IsMediaSessionEnabled() {
+// Media session is enabled on Android and Chrome OS to allow control of media
+// players as needed.
+#if defined(OS_ANDROID) || defined(OS_CHROMEOS)
+  return true;
+#else
+  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+  return command_line->HasSwitch(
+             media_session::switches::kEnableInternalMediaSession) ||
+         IsAudioFocusEnabled();
+#endif
+}
+
+}  // namespace media_session

services/media_session/public/cpp/switches.h

+// 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.
+
+#ifndef SERVICES_MEDIA_SESSION_PUBLIC_CPP_SWITCHES_H_
+#define SERVICES_MEDIA_SESSION_PUBLIC_CPP_SWITCHES_H_
+
+#include "base/component_export.h"
+#include "build/build_config.h"
+
+namespace media_session {
+namespace switches {
+
+COMPONENT_EXPORT(MEDIA_SESSION_CPP) extern const char kEnableAudioFocus[];
+COMPONENT_EXPORT(MEDIA_SESSION_CPP)
+extern const char kEnableAudioFocusDuckFlash[];
+
+#if !defined(OS_ANDROID)
+COMPONENT_EXPORT(MEDIA_SESSION_CPP)
+extern const char kEnableInternalMediaSession[];
+#endif  // !defined(OS_ANDROID)
+
+}  // namespace switches
+
+COMPONENT_EXPORT(MEDIA_SESSION_CPP) bool IsAudioFocusEnabled();
+
+// Based on the command line of the current process, determine if
+// audio focus duck flash should be enabled.
+COMPONENT_EXPORT(MEDIA_SESSION_CPP) bool IsAudioFocusDuckFlashEnabled();
+
+COMPONENT_EXPORT(MEDIA_SESSION_CPP) bool IsMediaSessionEnabled();
+
+}  // namespace media_session
+
+#endif  // SERVICES_MEDIA_SESSION_PUBLIC_CPP_SWITCHES_H_