[Presentation API] Add support for multiple URLs in PresentationRequest on Media Router UI side

chrome/browser/media/router/presentation_request.cc

 // 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.
 
 #include "chrome/browser/media/router/presentation_request.h"
 
 #include "chrome/browser/media/router/media_source_helper.h"
 
 namespace media_router {
 
 PresentationRequest::PresentationRequest(
     const RenderFrameHostId& render_frame_host_id,
-    const std::string& presentation_url,
+    const std::vector<std::string>& presentation_urls,
     const GURL& frame_url)
     : render_frame_host_id_(render_frame_host_id),
-      presentation_url_(presentation_url),
-      frame_url_(frame_url) {}
+      presentation_urls_(presentation_urls),
+      frame_url_(frame_url) {
+  DCHECK(!presentation_urls_.empty());
+}
 
 PresentationRequest::PresentationRequest(const PresentationRequest& other) =
     default;
 
 PresentationRequest::~PresentationRequest() = default;
 
 bool PresentationRequest::Equals(const PresentationRequest& other) const {
   return render_frame_host_id_ == other.render_frame_host_id_ &&
-         presentation_url_ == other.presentation_url_ &&
+         presentation_urls_ == other.presentation_urls_ &&
          frame_url_ == other.frame_url_;
 }
 
-MediaSource PresentationRequest::GetMediaSource() const {
-  return MediaSourceForPresentationUrl(presentation_url_);
+std::vector<MediaSource> PresentationRequest::GetMediaSources() const {
+  std::vector<MediaSource> sources;
+  for (const std::string& presentation_url : presentation_urls_)
+    sources.push_back(MediaSourceForPresentationUrl(presentation_url));
+  return sources;
 }
 
 }  // namespace media_router