Allow MediaSession in iframes to be routed

content/browser/media/session/media_session_service_impl.cc

Index: content/browser/media/session/media_session_service_impl.cc
diff --git a/content/browser/media/session/media_session_service_impl.cc b/content/browser/media/session/media_session_service_impl.cc
index 589823fab2b78f83bf7575e5044575a57642f1eb..b8ce61f8d17a60d4915f304ed146d493a1ef42c6 100644
--- a/content/browser/media/session/media_session_service_impl.cc
+++ b/content/browser/media/session/media_session_service_impl.cc
@@ -6,6 +6,7 @@
 
 #include "content/browser/media/session/media_metadata_sanitizer.h"
 #include "content/browser/media/session/media_session_impl.h"
+#include "content/browser/media/session/media_session_service_router.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/web_contents.h"
@@ -15,15 +16,15 @@ namespace content {
 MediaSessionServiceImpl::MediaSessionServiceImpl(
     RenderFrameHost* render_frame_host)
     : render_frame_host_(render_frame_host) {
-  MediaSessionImpl* session = GetMediaSession();
-  if (session)
-    session->SetMediaSessionService(this);
+  MediaSessionServiceRouter* router = GetMediaSessionServiceRouter();
+  if (router)
+    router->OnServiceCreated(this);
 }
 
 MediaSessionServiceImpl::~MediaSessionServiceImpl() {
-  MediaSessionImpl* session = GetMediaSession();
-  if (session && session->GetMediaSessionService() == this)
-    session->SetMediaSessionService(nullptr);
+  MediaSessionServiceRouter* router = GetMediaSessionServiceRouter();
+  if (router)
+    router->OnServiceDestroyed(this);
 }
 
 // static
@@ -50,34 +51,36 @@ void MediaSessionServiceImpl::SetMetadata(
         RenderProcessHost::CrashReportMode::GENERATE_CRASH_DUMP);
     return;
   }
+  metadata_ = metadata;
 
-  MediaSessionImpl* session = GetMediaSession();
-  if (session)
-    session->SetMetadata(metadata);
+  MediaSessionServiceRouter* router = GetMediaSessionServiceRouter();
+  if (router)
+    router->OnMediaSessionMetadataChanged(this);
 }
 
 void MediaSessionServiceImpl::EnableAction(
     blink::mojom::MediaSessionAction action) {
-  MediaSessionImpl* session = GetMediaSession();
-  if (session)
-    session->OnMediaSessionEnabledAction(action);
+  actions_.insert(action);
+  MediaSessionServiceRouter* router = GetMediaSessionServiceRouter();
+  if (router)
+    router->OnMediaSessionActionsChanged(this);
 }
 
 void MediaSessionServiceImpl::DisableAction(
     blink::mojom::MediaSessionAction action) {
-  MediaSessionImpl* session = GetMediaSession();
-  if (session)
-    session->OnMediaSessionDisabledAction(action);
+  actions_.erase(action);
+  MediaSessionServiceRouter* router = GetMediaSessionServiceRouter();
+  if (router)
+    router->OnMediaSessionActionsChanged(this);
 }
 
-MediaSessionImpl* MediaSessionServiceImpl::GetMediaSession() {
+MediaSessionServiceRouter*
+MediaSessionServiceImpl::GetMediaSessionServiceRouter() {
   WebContentsImpl* contents = static_cast<WebContentsImpl*>(
       WebContentsImpl::FromRenderFrameHost(render_frame_host_));
   if (!contents)
     return nullptr;
-  if (render_frame_host_ != contents->GetMainFrame())
-    return nullptr;
-  return MediaSessionImpl::Get(contents);
+  return MediaSessionImpl::Get(contents)->GetMediaSessionServiceRouter();
 }
 
 void MediaSessionServiceImpl::Bind(