[MediaRouter] Add implementation of PresentationServiceDelegate

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 "chrome/browser/media/router/presentation_helper.h"
 
 namespace media_router {
 
 // Helper library for protocol-specific media source object creation.
 
 // TODO(kmarshall): Should these creation methods be moved to the WebUI, which
 // (excluding Presentation API) is their only caller? The MR base code can be
 // Also, consider generating an is_mirroring state boolean at the time of URN
 // creation so that the mirroring status does not have to be determined from a
 // string prefix check.
 // These changes would allow the MR to handle MediaSource objects in the same
 // type agnostic fashion vs. having to format and parse URNs and track which
 // MediaSource types are mirroring-enabled.

[Wez, 2015/05/27 22:37:49]

Please remove this comment and replace it with a cleanup bug!

[haibinlu, 2015/05/28 21:44:02]

comment removed. They are not just for WebUI.

 
 // Returns MediaSource URI depending on the type of source.
 MediaSource ForTabMediaSource(int tab_id);
 MediaSource ForDesktopMediaSource();
 MediaSource ForCastAppMediaSource(const std::string& app_id);
 MediaSource ForPresentationUrl(const std::string& presentation_url);

[Wez, 2015/05/27 22:37:49]

These should be named e.g. MediaSourceForTab(), MediaSourceForDesktop() etc -
the current naming doesn't fit the style-guide, and the meanings are
non-obvious.

[haibinlu, 2015/05/28 21:44:02]

Done.

 
 // Returns true if |source| outputs its content via mirroring.
 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|.
+// |source| must be based on a presentation URL, e.g. created from
+// ForPresentationUrl, and must be valid.

[Wez, 2015/05/27 22:37:49]

So what does this return if it's _not_ from a valid MediaSource, or from one
that doesn't have a Presentation URL?

[haibinlu, 2015/05/28 21:44:02]

 Updated the comment.

+std::string GetPresentationUrl(const MediaSource& source);
+
 }  // namespace media_router
 
 #endif  // CHROME_BROWSER_MEDIA_ROUTER_MEDIA_SOURCE_HELPER_H_