[Media Router] Fix Cast MEDIA_STATUS updates.

The Cast SDK expects a MEDIA_STATUS message with an IDLE player after
stopping media.  This updates the Cast MRP to send it.

Bug: 1040185
Change-Id: Ieae8f30906026d2c9d067aecc31a61bcf9027eb9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2087700Reviewed-by: Takumi Fujimoto <takumif@chromium.org>
Commit-Queue: mark a. foltz <mfoltz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#748261}

chrome/browser/media/router/providers/cast/cast_session_tracker.cc

@@ -105,6 +105,7 @@ void CastSessionTracker::HandleReceiverStatusMessage(
 
 void CastSessionTracker::HandleMediaStatusMessage(const MediaSinkInternal& sink,
                                                   const base::Value& message) {
+  DVLOG(2) << "Initial MEDIA_STATUS: " << message;
   auto session_it = sessions_by_sink_id_.find(sink.sink().id());
   if (session_it == sessions_by_sink_id_.end()) {
     DVLOG(2) << "Got media status message, but no session for: "
@@ -131,17 +132,7 @@ void CastSessionTracker::HandleMediaStatusMessage(const MediaSinkInternal& sink,
     return;
   }
 
-  // First filter out any idle media objects.
-  updated_status->EraseListValueIf([](const base::Value& media) {
-    const std::string* player_state = media.FindStringKey("playerState");
-    return player_state && *player_state == "IDLE";
-  });
-
   base::Value::ListView media_list = updated_status->GetList();
-  if (media_list.size() > 1) {
-    DVLOG(2) << "Media list unexpectedly contains more than one live media: "
-             << media_list.size() << ", session: " << session_id;
-  }
 
   // Backfill messages from receivers to make them compatible with Cast SDK.
   for (auto& media : media_list) {
@@ -158,7 +149,7 @@ void CastSessionTracker::HandleMediaStatusMessage(const MediaSinkInternal& sink,
 
   CopySavedMediaFieldsToMediaList(session, media_list);
 
-  DVLOG(2) << "Final updated status: " << updated_status;
+  DVLOG(2) << "Final updated MEDIA_STATUS: " << *updated_status;
   session->UpdateMedia(*updated_status);
 
   base::Optional<int> request_id =

chrome/browser/media/router/providers/cast/cast_session_tracker_unittest.cc

@@ -169,9 +169,6 @@ TEST_F(CastSessionTrackerTest, HandleMediaStatusMessageBasic) {
   AddSinkAndSendReceiverStatusResponse();
 
   // Expect that:
-  //
-  // - Any 'status' entries with 'playerState' equal to "IDLE" are filtered out.
-  //
   // - The session ID is copied into the output message and all values in in the
   //   'status' list.
   //
@@ -187,8 +184,10 @@ TEST_F(CastSessionTrackerTest, HandleMediaStatusMessageBasic) {
         "sessionId": "theSessionId",
         "supportedMediaCommands": [],
       },
-    ],
-  })"),
+      {
+        "playerState": "IDLE",
+        "sessionId": "theSessionId"
+      }]})"),
                                               base::Optional<int>()));
 
   // This should call session_tracker_.HandleMediaStatusMessage(...).
@@ -211,6 +210,10 @@ TEST_F(CastSessionTrackerTest, HandleMediaStatusMessageBasic) {
     "playerState": "anything but IDLE",
     "sessionId": "theSessionId",
     "supportedMediaCommands": [],
+  },
+  {
+   "playerState": "IDLE",
+   "sessionId": "theSessionId"
   }])"));
 }
 
@@ -219,8 +222,6 @@ TEST_F(CastSessionTrackerTest, HandleMediaStatusMessageFancy) {
 
   // Expect that:
   //
-  // - Any 'status' entries with 'playerState' equal to "IDLE" are filtered out.
-  //
   // - The session ID is copied into the output message and all values in in the
   //   'status' list.
   //
@@ -241,7 +242,10 @@ TEST_F(CastSessionTrackerTest, HandleMediaStatusMessageFancy) {
         "supportedMediaCommands": ["pause"],
         "xyzzy": "xyzzyValue1",
       },
-    ],
+      {
+        "playerState": "IDLE",
+        "sessionId": "theSessionId"
+      }],
     "xyzzy": "xyzzyValue2",
   })"),
                                               base::make_optional(12345)));
@@ -270,6 +274,10 @@ TEST_F(CastSessionTrackerTest, HandleMediaStatusMessageFancy) {
     "sessionId": "theSessionId",
     "supportedMediaCommands": ["pause"],
     "xyzzy": "xyzzyValue1",
+  },
+  {
+    "playerState": "IDLE",
+    "sessionId": "theSessionId"
   }])"));
 }