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

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 GURL& frame_url)
-    : render_frame_host_id_(render_frame_host_id),
-      presentation_url_(presentation_url),
-      frame_url_(frame_url) {}
-
-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_ &&
-         frame_url_ == other.frame_url_;
-}
-
-MediaSource PresentationRequest::GetMediaSource() const {
-  return MediaSourceForPresentationUrl(presentation_url_);
-}
-
-}  // namespace media_router