WebLayer: add MediaRouter stub code.

This adds code to enable media router features, although the
implementation is still missing.

Notably,
- a feature flag is added to enable/disable MediaRouter code
- Media-related java, new and old, is moved into weblayer_private.media

Bug: 1057100
Change-Id: Ied1cfd60e19890166568fc3facbd012285c9fabf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2427289Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Evan Stade <estade@chromium.org>
Cr-Commit-Position: refs/heads/master@{#811910}

android_webview/expectations/system_webview_bundle.AndroidManifest.expected

@@ -76,6 +76,18 @@
         android:process=":webview_service"
         android:visibleToInstantApps="true">
     </provider>  # DIFF-ANCHOR: bfe37944
+    <receiver  # DIFF-ANCHOR: 1091f66b
+        android:exported="false"
+        android:name="com.google.android.gms.cast.framework.media.MediaIntentReceiver">
+    </receiver>  # DIFF-ANCHOR: 1091f66b
+    <service  # DIFF-ANCHOR: 41539e3c
+        android:exported="false"
+        android:name="com.google.android.gms.cast.framework.ReconnectionService">
+    </service>  # DIFF-ANCHOR: 41539e3c
+    <service  # DIFF-ANCHOR: 7dad1ec5
+        android:exported="false"
+        android:name="com.google.android.gms.cast.framework.media.MediaNotificationService">
+    </service>  # DIFF-ANCHOR: 7dad1ec5
     <service  # DIFF-ANCHOR: 3cd6d713
         android:exported="true"
         android:name="org.chromium.android_webview.services.AwMinidumpUploadJobService"

android_webview/expectations/trichrome_webview_bundle.AndroidManifest.expected

@@ -76,6 +76,18 @@
         android:process=":webview_service"
         android:visibleToInstantApps="true">
     </provider>  # DIFF-ANCHOR: bfe37944
+    <receiver  # DIFF-ANCHOR: 1091f66b
+        android:exported="false"
+        android:name="com.google.android.gms.cast.framework.media.MediaIntentReceiver">
+    </receiver>  # DIFF-ANCHOR: 1091f66b
+    <service  # DIFF-ANCHOR: 41539e3c
+        android:exported="false"
+        android:name="com.google.android.gms.cast.framework.ReconnectionService">
+    </service>  # DIFF-ANCHOR: 41539e3c
+    <service  # DIFF-ANCHOR: 7dad1ec5
+        android:exported="false"
+        android:name="com.google.android.gms.cast.framework.media.MediaNotificationService">
+    </service>  # DIFF-ANCHOR: 7dad1ec5
     <service  # DIFF-ANCHOR: 3cd6d713
         android:exported="true"
         android:name="org.chromium.android_webview.services.AwMinidumpUploadJobService"

base/android/resource_exclusions.gni

@@ -9,6 +9,7 @@ common_resource_exclusion_regex = "drawable[^/]*-xxxhdpi"
 common_resource_exclusion_exceptions = [
   "*shadow*",  # Combination of gradient & transparency cause pixelation.
   "*.9.*",  # Most nine-patches contain shadows.
+  "*ic_group_*",  # Appear only in xxxhdpi.
 ]
 
 # Remove WearOS resources (a couple exist in appcompat).

chrome/android/chrome_public_apk_tmpl.gni

@@ -153,7 +153,6 @@ template("chrome_public_common_apk_or_module_tmpl") {
     resource_exclusion_exceptions += [
       "*ic_file_download_white*",  # Bottom edge seems misaligned.
       "*ic_lock.*",  # Bottom edge seems misaligned.
-      "*ic_group_*",  # Appear only in xxxhdpi.
     ]
 
     if (min_sdk_version >= 21) {

weblayer/BUILD.gn

@@ -545,6 +545,10 @@ source_set("weblayer_lib_base") {
       "browser/js_communication/web_message_host_factory_proxy.h",
       "browser/js_communication/web_message_reply_proxy_impl.cc",
       "browser/js_communication/web_message_reply_proxy_impl.h",
+      "browser/media/local_presentation_manager_factory.cc",
+      "browser/media/local_presentation_manager_factory.h",
+      "browser/media/media_router_factory.cc",
+      "browser/media/media_router_factory.h",
       "browser/new_tab_callback_proxy.cc",
       "browser/new_tab_callback_proxy.h",
       "browser/safe_browsing/real_time_url_lookup_service_factory.cc",
@@ -606,6 +610,7 @@ source_set("weblayer_lib_base") {
       "//components/infobars/content",
       "//components/javascript_dialogs",
       "//components/location/android:settings",
+      "//components/media_router/browser",
       "//components/metrics",
       "//components/minidump_uploader",
       "//components/navigation_interception",

weblayer/browser/DEPS

@@ -30,6 +30,7 @@ include_rules = [
   "+components/keyed_service/content",
   "+components/keyed_service/core",
   "+components/language/core/browser",
+  "+components/media_router",
   "+components/metrics",
   "+components/navigation_interception",
   "+components/network_session_configurator",

weblayer/browser/browser_main_parts_impl.cc

@@ -50,7 +50,10 @@
 #include "net/base/network_change_notifier.h"
 #include "weblayer/browser/android/metrics/uma_utils.h"
 #include "weblayer/browser/java/jni/MojoInterfaceRegistrar_jni.h"
+#include "weblayer/browser/media/local_presentation_manager_factory.h"
+#include "weblayer/browser/media/media_router_factory.h"
 #include "weblayer/browser/weblayer_factory_impl_android.h"
+#include "weblayer/common/features.h"
 #endif
 
 #if defined(USE_X11)
@@ -86,6 +89,12 @@ void EnsureBrowserContextKeyedServiceFactoriesBuilt() {
   TranslateRankerFactory::GetInstance();
   PrerenderLinkManagerFactory::GetInstance();
   PrerenderManagerFactory::GetInstance();
+#if defined(OS_ANDROID)
+  if (base::FeatureList::IsEnabled(features::kMediaRouter)) {
+    LocalPresentationManagerFactory::GetInstance();
+    MediaRouterFactory::GetInstance();
+  }
+#endif
 }
 
 void StopMessageLoop(base::OnceClosure quit_closure) {

weblayer/browser/content_browser_client_impl.cc

@@ -114,6 +114,7 @@
 #include "components/cdm/browser/media_drm_storage_impl.h"  // nogncheck
 #include "components/crash/content/browser/crash_handler_host_linux.h"
 #include "components/embedder_support/android/metrics/android_metrics_service_client.h"
+#include "components/media_router/browser/presentation/presentation_service_delegate_impl.h"  // nogncheck
 #include "components/navigation_interception/intercept_navigation_delegate.h"
 #include "components/safe_browsing/core/realtime/policy_engine.h"  // nogncheck
 #include "components/safe_browsing/core/realtime/url_lookup_service.h"  // nogncheck
@@ -126,6 +127,7 @@
 #include "weblayer/browser/android_descriptors.h"
 #include "weblayer/browser/browser_context_impl.h"
 #include "weblayer/browser/devtools_manager_delegate_android.h"
+#include "weblayer/browser/media/media_router_factory.h"
 #include "weblayer/browser/safe_browsing/real_time_url_lookup_service_factory.h"
 #include "weblayer/browser/safe_browsing/safe_browsing_service.h"
 #include "weblayer/browser/tts_environment_android_impl.h"
@@ -631,6 +633,20 @@ bool ContentBrowserClientImpl::CanCreateWindow(
                  web_contents->GetBrowserContext())) != nullptr;
 }
 
+content::ControllerPresentationServiceDelegate*
+ContentBrowserClientImpl::GetControllerPresentationServiceDelegate(
+    content::WebContents* web_contents) {
+#if defined(OS_ANDROID)
+  if (base::FeatureList::IsEnabled(features::kMediaRouter)) {
+    MediaRouterFactory::DoPlatformInitIfNeeded();
+    return media_router::PresentationServiceDelegateImpl::
+        GetOrCreateForWebContents(web_contents);
+  }
+#endif
+
+  return nullptr;
+}
+
 std::vector<std::unique_ptr<content::NavigationThrottle>>
 ContentBrowserClientImpl::CreateThrottlesForNavigation(
     content::NavigationHandle* handle) {

weblayer/browser/content_browser_client_impl.h

@@ -90,6 +90,9 @@ class ContentBrowserClientImpl : public content::ContentBrowserClient {
                        bool user_gesture,
                        bool opener_suppressed,
                        bool* no_javascript_access) override;
+  content::ControllerPresentationServiceDelegate*
+  GetControllerPresentationServiceDelegate(
+      content::WebContents* web_contents) override;
   std::vector<std::unique_ptr<content::NavigationThrottle>>
   CreateThrottlesForNavigation(content::NavigationHandle* handle) override;
   content::GeneratedCodeCacheSettings GetGeneratedCodeCacheSettings(

weblayer/browser/java/BUILD.gn

@@ -114,8 +114,6 @@ android_library("java") {
     "org/chromium/weblayer_private/IntentUtils.java",
     "org/chromium/weblayer_private/InterceptNavigationDelegateClientImpl.java",
     "org/chromium/weblayer_private/LocaleChangedBroadcastReceiver.java",
-    "org/chromium/weblayer_private/MediaSessionManager.java",
-    "org/chromium/weblayer_private/MediaStreamManager.java",
     "org/chromium/weblayer_private/MojoInterfaceRegistrar.java",
     "org/chromium/weblayer_private/NavigationControllerImpl.java",
     "org/chromium/weblayer_private/NavigationImpl.java",
@@ -140,6 +138,9 @@ android_library("java") {
     "org/chromium/weblayer_private/WebLayerTabModalPresenter.java",
     "org/chromium/weblayer_private/WebMessageReplyProxyImpl.java",
     "org/chromium/weblayer_private/WebShareServiceFactory.java",
+    "org/chromium/weblayer_private/media/MediaRouterClientImpl.java",
+    "org/chromium/weblayer_private/media/MediaSessionManager.java",
+    "org/chromium/weblayer_private/media/MediaStreamManager.java",
     "org/chromium/weblayer_private/metrics/MetricsServiceClient.java",
     "org/chromium/weblayer_private/metrics/UmaUtils.java",
     "org/chromium/weblayer_private/permissions/PermissionRequestUtils.java",
@@ -193,6 +194,7 @@ android_library("java") {
     "//components/infobars/core:infobar_enums_java",
     "//components/javascript_dialogs/android:java",
     "//components/location/android:settings_java",
+    "//components/media_router/browser/android:java",
     "//components/metrics:metrics_java",
     "//components/minidump_uploader:minidump_uploader_java",
     "//components/navigation_interception/android:navigation_interception_java",
@@ -312,7 +314,6 @@ generate_jni("jni") {
     "org/chromium/weblayer_private/GoogleAccountsCallbackProxy.java",
     "org/chromium/weblayer_private/InfoBarContainer.java",
     "org/chromium/weblayer_private/LocaleChangedBroadcastReceiver.java",
-    "org/chromium/weblayer_private/MediaStreamManager.java",
     "org/chromium/weblayer_private/MojoInterfaceRegistrar.java",
     "org/chromium/weblayer_private/NavigationControllerImpl.java",
     "org/chromium/weblayer_private/NavigationImpl.java",
@@ -327,6 +328,8 @@ generate_jni("jni") {
     "org/chromium/weblayer_private/WebLayerImpl.java",
     "org/chromium/weblayer_private/WebMessageReplyProxyImpl.java",
     "org/chromium/weblayer_private/WebViewCompatibilityHelperImpl.java",
+    "org/chromium/weblayer_private/media/MediaRouterClientImpl.java",
+    "org/chromium/weblayer_private/media/MediaStreamManager.java",
     "org/chromium/weblayer_private/metrics/MetricsServiceClient.java",
     "org/chromium/weblayer_private/metrics/UmaUtils.java",
     "org/chromium/weblayer_private/permissions/PermissionRequestUtils.java",

weblayer/browser/java/org/chromium/weblayer_private/TabImpl.java

@@ -72,6 +72,8 @@ import org.chromium.weblayer_private.interfaces.IWebMessageCallbackClient;
 import org.chromium.weblayer_private.interfaces.ObjectWrapper;
 import org.chromium.weblayer_private.interfaces.ScrollNotificationType;
 import org.chromium.weblayer_private.interfaces.StrictModeWorkaround;
+import org.chromium.weblayer_private.media.MediaSessionManager;
+import org.chromium.weblayer_private.media.MediaStreamManager;
 
 import java.util.ArrayList;
 import java.util.HashMap;

weblayer/browser/java/org/chromium/weblayer_private/WebLayerFactoryImpl.java

@@ -74,7 +74,7 @@ public final class WebLayerFactoryImpl extends IWebLayerFactory.Stub {
     }
 
     @CalledByNative
-    static int getClientMajorVersion() {
+    public static int getClientMajorVersion() {
         if (sClientMajorVersion == 0) {
             throw new IllegalStateException(
                     "This should only be called once WebLayer is initialized");

weblayer/browser/java/org/chromium/weblayer_private/WebLayerImpl.java

@@ -74,6 +74,8 @@ import org.chromium.weblayer_private.interfaces.IWebLayer;
 import org.chromium.weblayer_private.interfaces.IWebLayerClient;
 import org.chromium.weblayer_private.interfaces.ObjectWrapper;
 import org.chromium.weblayer_private.interfaces.StrictModeWorkaround;
+import org.chromium.weblayer_private.media.MediaSessionManager;
+import org.chromium.weblayer_private.media.MediaStreamManager;
 import org.chromium.weblayer_private.metrics.MetricsServiceClient;
 import org.chromium.weblayer_private.metrics.UmaUtils;
 

weblayer/browser/java/org/chromium/weblayer_private/WebLayerNotificationChannels.java

@@ -25,8 +25,9 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
+/** Defines notification channels for WebLayer. */
 @TargetApi(Build.VERSION_CODES.O)
-class WebLayerNotificationChannels extends ChannelDefinitions {
+public class WebLayerNotificationChannels extends ChannelDefinitions {
     /**
      * Version number identifying the current set of channels. This must be incremented whenever the
      * set of channels returned by {@link #getStartupChannelIds()} or {@link #getLegacyChannelIds()}

weblayer/browser/java/org/chromium/weblayer_private/WebLayerNotificationWrapperBuilder.java

@@ -22,7 +22,7 @@ import org.chromium.components.browser_ui.notifications.NotificationWrapperStand
 import org.chromium.components.browser_ui.notifications.channels.ChannelsInitializer;
 
 /** A notification builder for WebLayer which has extra logic to make icons work correctly. */
-final class WebLayerNotificationWrapperBuilder extends NotificationWrapperStandardBuilder {
+public final class WebLayerNotificationWrapperBuilder extends NotificationWrapperStandardBuilder {
     /** Creates a notification builder. */
     public static WebLayerNotificationWrapperBuilder create(
             @WebLayerNotificationChannels.ChannelId String channelId,

weblayer/browser/java/org/chromium/weblayer_private/media/MediaRouterClientImpl.java

+// 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.
+
+package org.chromium.weblayer_private.media;
+
+import android.content.Intent;
+
+import androidx.fragment.app.FragmentManager;
+
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
+import org.chromium.components.browser_ui.media.MediaNotificationInfo;
+import org.chromium.components.media_router.MediaRouterClient;
+import org.chromium.content_public.browser.WebContents;
+import org.chromium.weblayer_private.IntentUtils;
+import org.chromium.weblayer_private.TabImpl;
+
+/** Provides WebLayer-specific behavior for Media Router. */
+@JNINamespace("weblayer")
+public class MediaRouterClientImpl extends MediaRouterClient {
+    private MediaRouterClientImpl() {}
+
+    @Override
+    public int getTabId(WebContents webContents) {
+        TabImpl tab = TabImpl.fromWebContents(webContents);
+        return tab == null ? -1 : tab.getId();
+    }
+
+    @Override
+    public Intent createBringTabToFrontIntent(int tabId) {
+        return IntentUtils.createBringTabToFrontIntent(tabId);
+    }
+
+    @Override
+    public void showNotification(MediaNotificationInfo notificationInfo) {
+        // TODO: implement.
+    }
+
+    @Override
+    public FragmentManager getSupportFragmentManager(WebContents initiator) {
+        return null;
+    }
+
+    @CalledByNative
+    public static void initialize() {
+        if (MediaRouterClient.getInstance() != null) return;
+
+        MediaRouterClient.setInstance(new MediaRouterClientImpl());
+    }
+}

weblayer/browser/java/org/chromium/weblayer_private/MediaSessionManager.java → weblayer/browser/java/org/chromium/weblayer_private/media/MediaSessionManager.java

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-package org.chromium.weblayer_private;
+package org.chromium.weblayer_private.media;
 
 import android.app.Service;
 import android.content.Intent;
@@ -16,6 +16,10 @@ import org.chromium.components.browser_ui.notifications.ForegroundServiceUtils;
 import org.chromium.components.browser_ui.notifications.NotificationMetadata;
 import org.chromium.components.browser_ui.notifications.NotificationWrapper;
 import org.chromium.components.browser_ui.notifications.NotificationWrapperBuilder;
+import org.chromium.weblayer_private.IntentUtils;
+import org.chromium.weblayer_private.WebLayerImpl;
+import org.chromium.weblayer_private.WebLayerNotificationChannels;
+import org.chromium.weblayer_private.WebLayerNotificationWrapperBuilder;
 
 /**
  * A glue class for MediaSession.
@@ -23,10 +27,10 @@ import org.chromium.components.browser_ui.notifications.NotificationWrapperBuild
  * It also manages the lifetime of {@link MediaNotificationController} and the {@link Service}
  * associated with the notification.
  */
-class MediaSessionManager {
+public class MediaSessionManager {
     private static int sNotificationId;
 
-    static void serviceStarted(Service service, Intent intent) {
+    public static void serviceStarted(Service service, Intent intent) {
         MediaNotificationController controller = getController();
         if (controller != null && controller.processIntent(service, intent)) return;
 
@@ -41,13 +45,13 @@ class MediaSessionManager {
         service.stopSelf();
     }
 
-    static void serviceDestroyed() {
+    public static void serviceDestroyed() {
         MediaNotificationController controller = getController();
         if (controller != null) controller.onServiceDestroyed();
         MediaNotificationManager.clear(getNotificationId());
     }
 
-    static MediaSessionHelper.Delegate createMediaSessionHelperDelegate(int tabId) {
+    public static MediaSessionHelper.Delegate createMediaSessionHelperDelegate(int tabId) {
         return new MediaSessionHelper.Delegate() {
             @Override
             public Intent createBringTabToFrontIntent() {

weblayer/browser/java/org/chromium/weblayer_private/MediaStreamManager.java → weblayer/browser/java/org/chromium/weblayer_private/media/MediaStreamManager.java

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-package org.chromium.weblayer_private;
+package org.chromium.weblayer_private.media;
 
 import android.app.NotificationManager;
 import android.content.Context;
@@ -25,6 +25,12 @@ import org.chromium.components.browser_ui.notifications.PendingIntentProvider;
 import org.chromium.components.webrtc.MediaCaptureNotificationUtil;
 import org.chromium.components.webrtc.MediaCaptureNotificationUtil.MediaType;
 import org.chromium.content_public.browser.WebContents;
+import org.chromium.weblayer_private.IntentUtils;
+import org.chromium.weblayer_private.TabImpl;
+import org.chromium.weblayer_private.WebLayerFactoryImpl;
+import org.chromium.weblayer_private.WebLayerImpl;
+import org.chromium.weblayer_private.WebLayerNotificationChannels;
+import org.chromium.weblayer_private.WebLayerNotificationWrapperBuilder;
 import org.chromium.weblayer_private.interfaces.IMediaCaptureCallbackClient;
 import org.chromium.weblayer_private.interfaces.ObjectWrapper;
 

weblayer/browser/media/local_presentation_manager_factory.cc

+// 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.
+
+#include "weblayer/browser/media/local_presentation_manager_factory.h"
+
+#include "base/no_destructor.h"
+
+namespace weblayer {
+
+// static
+LocalPresentationManagerFactory*
+LocalPresentationManagerFactory::GetInstance() {
+  static base::NoDestructor<LocalPresentationManagerFactory> instance;
+  return instance.get();
+}
+
+LocalPresentationManagerFactory::LocalPresentationManagerFactory() = default;
+LocalPresentationManagerFactory::~LocalPresentationManagerFactory() = default;
+
+content::BrowserContext*
+LocalPresentationManagerFactory::GetBrowserContextToUse(
+    content::BrowserContext* context) const {
+  return context;
+}
+
+}  // namespace weblayer

weblayer/browser/media/local_presentation_manager_factory.h

+// 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 WEBLAYER_BROWSER_MEDIA_LOCAL_PRESENTATION_MANAGER_FACTORY_H_
+#define WEBLAYER_BROWSER_MEDIA_LOCAL_PRESENTATION_MANAGER_FACTORY_H_
+
+#include "components/media_router/browser/presentation/local_presentation_manager_factory.h"
+
+namespace base {
+template <typename T>
+class NoDestructor;
+}
+
+namespace content {
+class BrowserContext;
+}
+
+namespace weblayer {
+
+// A version of LocalPresentationManagerFactory that does not redirect from
+// incognito to normal context.
+class LocalPresentationManagerFactory
+    : public media_router::LocalPresentationManagerFactory {
+ public:
+  LocalPresentationManagerFactory(const LocalPresentationManagerFactory&) =
+      delete;
+  LocalPresentationManagerFactory& operator=(
+      const LocalPresentationManagerFactory&) = delete;
+
+  static LocalPresentationManagerFactory* GetInstance();
+
+ private:
+  friend base::NoDestructor<LocalPresentationManagerFactory>;
+
+  LocalPresentationManagerFactory();
+  ~LocalPresentationManagerFactory() override;
+
+  // BrowserContextKeyedServiceFactory interface.
+  content::BrowserContext* GetBrowserContextToUse(
+      content::BrowserContext* context) const override;
+};
+
+}  // namespace weblayer
+
+#endif  // WEBLAYER_BROWSER_MEDIA_LOCAL_PRESENTATION_MANAGER_FACTORY_H_

weblayer/browser/media/media_router_factory.cc

+// 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.
+
+#include "weblayer/browser/media/media_router_factory.h"
+
+#include "base/android/jni_android.h"
+#include "base/no_destructor.h"
+#include "components/media_router/browser/android/media_router_android.h"
+#include "components/media_router/browser/android/media_router_dialog_controller_android.h"
+#include "components/media_router/browser/media_router_dialog_controller.h"
+#include "content/public/browser/browser_context.h"
+#include "weblayer/browser/java/jni/MediaRouterClientImpl_jni.h"
+
+namespace weblayer {
+
+// static
+MediaRouterFactory* MediaRouterFactory::GetInstance() {
+  static base::NoDestructor<MediaRouterFactory> instance;
+  return instance.get();
+}
+
+// static
+void MediaRouterFactory::DoPlatformInitIfNeeded() {
+  static bool init_done = false;
+  if (init_done)
+    return;
+
+  Java_MediaRouterClientImpl_initialize(base::android::AttachCurrentThread());
+
+  media_router::MediaRouterDialogController::SetGetOrCreate(
+      base::BindRepeating([](content::WebContents* web_contents) {
+        DCHECK(web_contents);
+        // This call does nothing if the controller already exists.
+        media_router::MediaRouterDialogControllerAndroid::CreateForWebContents(
+            web_contents);
+        return static_cast<media_router::MediaRouterDialogController*>(
+            media_router::MediaRouterDialogControllerAndroid::FromWebContents(
+                web_contents));
+      }));
+  init_done = true;
+}
+
+MediaRouterFactory::MediaRouterFactory() = default;
+MediaRouterFactory::~MediaRouterFactory() = default;
+
+content::BrowserContext* MediaRouterFactory::GetBrowserContextToUse(
+    content::BrowserContext* context) const {
+  return context;
+}
+
+KeyedService* MediaRouterFactory::BuildServiceInstanceFor(
+    content::BrowserContext* context) const {
+  media_router::MediaRouterBase* media_router =
+      new media_router::MediaRouterAndroid();
+  media_router->Initialize();
+  return media_router;
+}
+
+}  // namespace weblayer

weblayer/browser/media/media_router_factory.h

+// 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 WEBLAYER_BROWSER_MEDIA_MEDIA_ROUTER_FACTORY_H_
+#define WEBLAYER_BROWSER_MEDIA_MEDIA_ROUTER_FACTORY_H_
+
+#include "components/media_router/browser/media_router_factory.h"
+
+namespace base {
+template <typename T>
+class NoDestructor;
+}
+
+namespace content {
+class BrowserContext;
+}
+
+namespace weblayer {
+
+class MediaRouterFactory : public media_router::MediaRouterFactory {
+ public:
+  MediaRouterFactory(const MediaRouterFactory&) = delete;
+  MediaRouterFactory& operator=(const MediaRouterFactory&) = delete;
+
+  static MediaRouterFactory* GetInstance();
+
+  // Performs platform and WebLayer-specific initialization for media_router.
+  static void DoPlatformInitIfNeeded();
+
+ private:
+  friend base::NoDestructor<MediaRouterFactory>;
+
+  MediaRouterFactory();
+  ~MediaRouterFactory() override;
+
+  // MediaRouterFactory:
+  content::BrowserContext* GetBrowserContextToUse(
+      content::BrowserContext* context) const override;
+  KeyedService* BuildServiceInstanceFor(
+      content::BrowserContext* context) const override;
+};
+
+}  // namespace weblayer
+
+#endif  // WEBLAYER_BROWSER_MEDIA_MEDIA_ROUTER_FACTORY_H_

weblayer/common/features.cc

@@ -9,6 +9,11 @@ namespace features {
 
 // Weblayer features in alphabetical order.
 
+// Covers all media router features, i.e. Presentation API, Remote Playback API,
+// and Media Fling (automatic casting of html5 videos).
+const base::Feature kMediaRouter{"WebLayerMediaRouter",
+                                 base::FEATURE_DISABLED_BY_DEFAULT};
+
 // Safebrowsing support for weblayer.
 const base::Feature kWebLayerSafeBrowsing{"WebLayerSafeBrowsing",
                                           base::FEATURE_ENABLED_BY_DEFAULT};

weblayer/common/features.h

@@ -12,6 +12,8 @@ namespace features {
 
 // Weblayer features in alphabetical order.
 
+extern const base::Feature kMediaRouter;
+
 extern const base::Feature kWebLayerSafeBrowsing;
 
 }  // namespace features