Update SupportsUserData uses with unique_ptr.

chrome/browser/media/cast_remoting_connector.h

Index: chrome/browser/media/cast_remoting_connector.h
diff --git a/chrome/browser/media/cast_remoting_connector.h b/chrome/browser/media/cast_remoting_connector.h
index 989fb7c39c834d6c88949910aa04b125219cb84c..9fb6d8278aaf2b091c61504ba7ef76f1dcb4c1b6 100644
--- a/chrome/browser/media/cast_remoting_connector.h
+++ b/chrome/browser/media/cast_remoting_connector.h
@@ -66,6 +66,8 @@ class CastRemotingConnector
     : public base::SupportsUserData::Data,
       public media_router::MediaRoutesObserver {
  public:
+  ~CastRemotingConnector() final;
+
   // Returns the instance of the CastRemotingConnector associated with
   // |source_contents|, creating a new instance if needed.
   static CastRemotingConnector* Get(content::WebContents* source_contents);
@@ -99,8 +101,6 @@ class CastRemotingConnector
   CastRemotingConnector(media_router::MediaRouter* router,
                         const media_router::MediaSource::Id& media_source_id);
 
-  ~CastRemotingConnector() final;
-
   // Creates a RemotingBridge that implements the requested Remoter service, and
   // binds it to the interface |request|.
   void CreateBridge(media::mojom::RemotingSourcePtr source,