NOT FOR LANDING Introduce and use WebMediaSession

public/BUILD.gn

 # Copyright 2014 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.
 
 import("//tools/grit/grit_rule.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")
 }
 
@@ skipping 195 matching lines @@
     "platform/WebHistoryScrollRestorationType.h",
     "platform/WebServiceWorkerClientsClaimCallbacks.h",
     "platform/WebFileWriterClient.h",
     "platform/modules/bluetooth/WebBluetoothGATTService.h",
     "platform/modules/bluetooth/WebBluetoothError.h",
     "platform/modules/bluetooth/WebBluetoothDevice.h",
     "platform/modules/bluetooth/WebBluetooth.h",
     "platform/modules/bluetooth/WebRequestDeviceOptions.h",
     "platform/modules/bluetooth/WebBluetoothGATTCharacteristic.h",
     "platform/modules/bluetooth/WebBluetoothGATTRemoteServer.h",
+    "platform/modules/mediasession/WebMediaSession.h",
     "platform/modules/navigator_services/WebServicePortProviderClient.h",
     "platform/modules/navigator_services/WebServicePortProvider.h",
     "platform/modules/navigator_services/WebServicePort.h",
     "platform/modules/permissions/WebPermissionObserver.h",
     "platform/modules/permissions/WebPermissionClient.h",
     "platform/modules/permissions/WebPermissionStatus.h",
     "platform/modules/permissions/WebPermissionType.h",
     "platform/modules/presentation/WebPresentationSessionClient.h",
     "platform/modules/presentation/WebPresentationClient.h",
     "platform/modules/presentation/WebPresentationController.h",
@@ skipping 421 matching lines @@
 grit("image_resources") {
   output_dir = "$root_gen_dir/blink/public/resources"
   use_qualified_include = true
   source = "blink_image_resources.grd"
   outputs = [
     "grit/blink_image_resources.h",
     "blink_image_resources_100_percent.pak",
     "blink_image_resources_200_percent.pak",
   ]
 }