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 385 matching lines @@
     "platform/WebDataConsumerHandle.h",
     "platform/WebPrivatePtr.h",
     "platform/WebServiceWorker.h",
     "platform/WebRTCICECandidate.h",
     "platform/WebServiceWorkerProxy.h",
     "platform/WebFallbackThemeEngine.h",
     "platform/WebGraphicsContext3DProvider.h",
     "platform/WebServiceWorkerState.h",
     "platform/WebMediaPlayer.h",
     "platform/WebMediaPlayerClient.h",
+    "platform/WebMediaSession.h",
     "platform/WebScrollbarThemeGeometry.h",
     "platform/WebUnitTestSupport.h",
     "platform/WebFilterKeyframe.h",
     "platform/WebBlobRegistry.h",
     "platform/WebSpeechSynthesisUtterance.h",
     "platform/WebURLLoader.h",
     "platform/WebGestureCurve.h",
     "platform/WebCompositorAnimationPlayerClient.h",
     "platform/WebMediaDeviceInfo.h",
     "platform/WebFileSystemCallbacks.h",
@@ skipping 229 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",
   ]
 }