Add media router common classes and unittests.

chrome/browser/media/router/media_route.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_ROUTE_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_MEDIA_ROUTE_H_
+
+#include <string>
+
+#include "base/logging.h"
+#include "base/values.h"
+#include "chrome/browser/media/router/media_route_id.h"
+#include "chrome/browser/media/router/media_sink.h"
+#include "chrome/browser/media/router/media_source.h"
+#include "url/gurl.h"
+
+namespace media_router {
+
+typedef int64 RouteRequestId;

[mark a. foltz, 2015/03/02 21:40:09]

using is now preferred for type aliasing.

http://en.cppreference.com/w/cpp/language/type_alias

[Kevin M, 2015/03/03 21:53:18]

Done.

[Kevin M, 2015/03/03 21:53:19]

Done.

+extern const int64 kInvalidRouteRequestId;

[mark a. foltz, 2015/03/02 21:40:09]

s/int64/RouteRequestId/

[Kevin M, 2015/03/03 21:53:19]

Done.

+
+// For now, a simple transition graph: NEW -> CONNECTED -> CLOSED.
+enum MediaRouteState {
+  // The route is new and not yet connected to a sink.
+  MEDIA_ROUTE_STATE_NEW,
+  // The route is active and connected to a sink.
+  MEDIA_ROUTE_STATE_CONNECTED,
+  // The route has been disconnected.
+  MEDIA_ROUTE_STATE_CLOSED
+};
+
+// TODO(mfoltz): Add errors as needed.

[mark a. foltz, 2015/03/02 21:40:09]

Please touch base with Derek and see if there is an error reporting path from
the service that needs this.  If so define error values that make sense,
otherwise I would remove it.

[Kevin M, 2015/03/03 21:53:19]

Removed.

+enum MediaRouteError {
+  MEDIA_ROUTE_ERROR_NONE
+};
+
+// A MediaRoute encapsulates an application's means of routing media from a
+// source to a sink.
+class MediaRoute {

[DaleCurtis, 2015/03/02 23:14:33]

You'll likely need EXPORT definitions if you plan to use these in unit tests.

[Kevin M, 2015/03/03 21:53:18]

I'm building with component=shared_library and haven't seen any errors yet. How
do I tell if this is necessary or not?

+ public:
+  // Ctor. Do not call directly, use MediaRouteFactory instead.
+  // TODO(mfoltz): Make private and friend MRF

[mark a. foltz, 2015/03/02 21:40:09]

Can we do this now?

I feel we should do this to control allocation of media_route_ids.  The
MediaRouter implementation should really be the only thing that can create
MediaRoute objects, and it could instantiate a factory object that is friended
by this.

[Kevin M, 2015/03/03 21:53:19]

Done.

+  // |media_route_id|: Uniquely identifies the route among active

[mark a. foltz, 2015/03/02 21:40:09]

For this to be true the (to be implemented) factory will need to be a singleton
and shared among the MediaRouter implementations (which are becoming
profile-keyed).

[Kevin M, 2015/03/03 21:53:19]

Done.

+  // instances.
+  // |type|: Type of media route.
+  // |media_source|: Description of source of the route.
+  // |sink_id|: ID of the MediaSink of the route.
+  // |description|: Description of the route to be displayed.
+  // |is_local|: true if the route was created initiated from this Chrome

[mark a. foltz, 2015/03/02 21:40:09]

"created instantiated" seems redundant.

Can you clarify "this instance"?  Is this per-browser process or per-profile?

[Kevin M, 2015/03/03 21:53:18]

Per browser process. Done.

+  // instance.
+  MediaRoute(const MediaRouteId& media_route_id,
+             const MediaSource& media_source,
+             const MediaSinkId& sink_id,
+             const std::string& description,
+             bool is_local);
+
+  ~MediaRoute();
+
+  // The media route identifier.
+  const MediaRouteId& media_route_id() const { return media_route_id_; }
+
+  // The state of the media route.
+  MediaRouteState state() const { return state_; }
+
+  // The media source being routed.
+  const MediaSource& media_source() const { return media_source_; }
+
+  // The sink being routed to.

[mark a. foltz, 2015/03/02 21:40:09]

The ID of the sink...

[Kevin M, 2015/03/03 21:53:19]

Done.

+  const MediaSinkId& sink_id() const { return sink_id_; }
+
+  // The description of the media route activity.

[mark a. foltz, 2015/03/02 21:40:08]

An example would be helpful.

Will this need to be localized in any way?

[Kevin M, 2015/03/03 21:53:18]

Good question - do you think we should push UI locale down to the component
extension, or should we take locale/message pairs here?

I'm thinking the former might be preferable. We could change the Mojo call
GetMediaRouterInstanceId() to GetMediaRouterInstanceInfo(), which would return
locale in addition to the instance ID GUID.

GetMediaRouterInstanceId() => (string instance_id, string locale);

[Kevin M, 2015/03/03 22:18:27]

Talked with haibinlu@ about this - the description is free text sent by the
receiver, which is spawned with the user's locale and is responsible for
returning locale-appropriate strings. So no, it shouldn't need localization.

+  const std::string& description() const { return description_; }
+
+  // Returns |true| if the route is initiated locally.

[mark a. foltz, 2015/03/02 21:40:09]

I might elaborate a little:

"if the route was created locally (versus discovered by a media route
provider)." 

[Kevin M, 2015/03/03 21:53:19]

Done.

+  bool is_local() const { return is_local_; }
+
+  bool operator==(const MediaRoute& other) const;
+  bool operator!=(const MediaRoute& other) const;
+
+ private:
+  MediaRouteId media_route_id_;
+  MediaSource media_source_;
+  MediaSinkId sink_id_;
+  std::string description_;
+  bool is_local_;
+  MediaRouteState state_;
+  // TODO(imcheng): Add icon URL.

[mark a. foltz, 2015/03/02 21:40:09]

Still valid?

[Kevin M, 2015/03/03 21:53:18]

Done.

+};
+
+// Response to a media route request to the Media Route Provider.

[mark a. foltz, 2015/03/02 21:40:09]

"...from a Media Route Provider"

[Kevin M, 2015/03/03 21:53:18]

Done.

+class MediaRouteResponse {
+ public:
+  // Creates a MediaRouteResponse object that indicates success.

[mark a. foltz, 2015/03/02 21:40:08]

Only Media Router implementations should be creating these IIUC. Should they be
declared protected and virtual in MediaRouter? 

[Kevin M, 2015/03/03 21:53:18]

Done. Removed it from here. Will just ack the comments here and defer them to
the CL that lands media_router.h.

+  // |request_id|: ID of original request.

[mark a. foltz, 2015/03/02 21:40:09]

s/request_id/route_request_id/g to be explicit about the nature of the request.

[Kevin M, 2015/03/03 21:53:18]

Acknowledged.

+  // |route|: Route created.
+  static scoped_ptr<MediaRouteResponse> Success(
+      const RouteRequestId& request_id, const MediaRoute& route);
+  // Creates a MediaRouteResponse object that indicates failure.
+  // |request_id|: ID of original request.
+  // |error|: Failure reason.
+  static scoped_ptr<MediaRouteResponse> Error(
+      const RouteRequestId& request_id, const std::string& error);

[mark a. foltz, 2015/03/02 21:40:09]

Should we use a MediaRouteError instead of the error string?  If we want to have
any intelligent error handling from a client, we need an enum.

[Kevin M, 2015/03/03 21:53:18]

Acknowledged.

+
+  ~MediaRouteResponse();
+
+  const RouteRequestId& request_id() const { return request_id_; }
+  // Returns a pointer to the route created. Returns nullptr if response
+  // indicates error.
+  const MediaRoute* route() const { return route_.get(); }
+  const std::string& error() const { return error_; }
+
+ private:
+  MediaRouteResponse(
+      const RouteRequestId& request_id, const MediaRoute& route);
+  MediaRouteResponse(
+      const RouteRequestId& request_id, const std::string& error);
+  MediaRouteResponse(const MediaRouteResponse& other);
+
+  // ID of original request. Set in all MediaRouteResponse objects, regardless
+  // of success/failure.
+  RouteRequestId request_id_;
+  // The route created as a result of the request. Points to a valid MediaRoute
+  // iff the response indicates success, nullptr otherwise.
+  scoped_ptr<MediaRoute> route_;

[mark a. foltz, 2015/03/02 21:40:09]

It's odd that the response object owns the lifetime of the media route.  That
implies that the caller has to keep the response around as long as it wants to
use the route, or explicitly take ownership, which doesn't seem to be supported.
 How should callers keep |route_| alive?

[Kevin M, 2015/03/03 21:53:19]

Acknowledged.

+  // Set to empty string if response indicates success, otherwise set to the
+  // failure reason.
+  std::string error_;
+};
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_MEDIA_ROUTE_H_