Make MediaSession available on Desktop

content/browser/media/media_web_contents_observer.cc

Index: content/browser/media/media_web_contents_observer.cc
diff --git a/content/browser/media/media_web_contents_observer.cc b/content/browser/media/media_web_contents_observer.cc
index ef3f5dc9c9d5194480f0a5c99e351f872ac0491c..a2713aba92f61c5cfcd3a364c0f202c1ec312db7 100644
--- a/content/browser/media/media_web_contents_observer.cc
+++ b/content/browser/media/media_web_contents_observer.cc
@@ -10,6 +10,7 @@
 #include "build/build_config.h"
 #include "content/browser/media/audible_metrics.h"
 #include "content/browser/media/audio_stream_monitor.h"
+#include "content/browser/media/session/browser_media_session_manager.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/common/media/media_player_delegate_messages.h"
 #include "content/public/browser/render_frame_host.h"
@@ -32,6 +33,25 @@ MediaWebContentsObserver::MediaWebContentsObserver(WebContents* web_contents)
 
 MediaWebContentsObserver::~MediaWebContentsObserver() {}
 
+BrowserMediaSessionManager*
+MediaWebContentsObserver::GetMediaSessionManager(
+    RenderFrameHost* render_frame_host) {
+  auto it = media_session_managers_.find(render_frame_host);
+  if (it != media_session_managers_.end())
+    return it->second;
+
+  BrowserMediaSessionManager* manager =
+      new BrowserMediaSessionManager(render_frame_host);
+  media_session_managers_.set(render_frame_host, base::WrapUnique(manager));
+  return manager;
+}
+
+void MediaWebContentsObserver::SetMediaSessionManagerForTest(
+    RenderFrameHost* render_frame_host,
+    std::unique_ptr<BrowserMediaSessionManager> manager) {
+  media_session_managers_.set(render_frame_host, std::move(manager));
+}
+
 void MediaWebContentsObserver::WebContentsDestroyed() {
   g_audible_metrics.Get().UpdateAudibleWebContentsState(web_contents(), false);
 }
@@ -40,6 +60,7 @@ void MediaWebContentsObserver::RenderFrameDeleted(
     RenderFrameHost* render_frame_host) {
   ClearPowerSaveBlockers(render_frame_host);
   session_controllers_manager_.RenderFrameDeleted(render_frame_host);
+  media_session_managers_.erase(render_frame_host);
 }
 
 void MediaWebContentsObserver::MaybeUpdateAudibleState() {