Pass origin to StartObservingMediaSinks.

chrome/browser/media/router/media_source_helper.h

 // Copyright 2015 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.
 
 #ifndef CHROME_BROWSER_MEDIA_ROUTER_MEDIA_SOURCE_HELPER_H_
 #define CHROME_BROWSER_MEDIA_ROUTER_MEDIA_SOURCE_HELPER_H_
 
 #include <string>
 
 #include "chrome/browser/media/router/media_source.h"
+#include "url/gurl.h"
 
 namespace media_router {
 
 // Helper library for protocol-specific media source object creation.
 // Returns MediaSource URI depending on the type of source.
 MediaSource MediaSourceForTab(int tab_id);
 MediaSource MediaSourceForDesktop();
 MediaSource MediaSourceForCastApp(const std::string& app_id);
-MediaSource MediaSourceForPresentationUrl(const std::string& presentation_url);
+MediaSource MediaSourceForPresentationUrl(const std::string& presentation_url,
+                                          const std::string& origin);
+
+GURL OriginForDesktop();
 
 // Returns true if |source| outputs its content via mirroring.
 bool IsDesktopMirroringMediaSource(const MediaSource& source);
 bool IsTabMirroringMediaSource(const MediaSource& source);
 bool IsMirroringMediaSource(const MediaSource& source);
 
 // Checks that |source| is a parseable URN and is of a known type.
 // Does not deeper protocol-level syntax checks.
 bool IsValidMediaSource(const MediaSource& source);
 
 // Extracts the presentation URL from |source|.
 // If |source| is invalid, an empty string is returned.
 std::string PresentationUrlFromMediaSource(const MediaSource& source);
 
 // Returns true if |source| is a valid presentation URL.
 bool IsValidPresentationUrl(const std::string& url);
 
 }  // namespace media_router
 
 #endif  // CHROME_BROWSER_MEDIA_ROUTER_MEDIA_SOURCE_HELPER_H_