[Presentation API / Media Router] Clean up default pres URL logic.

chrome/browser/media/router/create_presentation_session_request.cc

Index: chrome/browser/media/router/create_presentation_session_request.cc
diff --git a/chrome/browser/media/router/create_presentation_session_request.cc b/chrome/browser/media/router/create_presentation_session_request.cc
index b3b4bc851e45d1547f98bdfce75553cb1bd10fdd..b17abeae304d45952530288f446de8ad141860c6 100644
--- a/chrome/browser/media/router/create_presentation_session_request.cc
+++ b/chrome/browser/media/router/create_presentation_session_request.cc
@@ -12,12 +12,12 @@ using content::PresentationError;
 namespace media_router {
 
 CreatePresentationSessionRequest::CreatePresentationSessionRequest(
+    const RenderFrameHostId& render_frame_host_id,
     const std::string& presentation_url,
     const GURL& frame_url,
     const PresentationSessionSuccessCallback& success_cb,
     const PresentationSessionErrorCallback& error_cb)
-    : media_source_(MediaSourceForPresentationUrl(presentation_url)),
-      frame_url_(frame_url),
+    : presentation_request_(render_frame_host_id, presentation_url, frame_url),
       success_cb_(success_cb),
       error_cb_(error_cb),
       cb_invoked_(false) {
@@ -37,10 +37,9 @@ void CreatePresentationSessionRequest::InvokeSuccessCallback(
     const MediaRoute::Id& route_id) {
   DCHECK(!cb_invoked_);
   if (!cb_invoked_) {
-    // Overwrite presentation ID.
     success_cb_.Run(
         content::PresentationSessionInfo(
-            PresentationUrlFromMediaSource(media_source_), presentation_id),
+            presentation_request_.presentation_url(), presentation_id),
         route_id);
     cb_invoked_ = true;
   }