[Media Router] Make per-hostname cast mode selections persist

chrome/browser/ui/webui/media_router/media_router_webui_message_handler.cc

Index: chrome/browser/ui/webui/media_router/media_router_webui_message_handler.cc
diff --git a/chrome/browser/ui/webui/media_router/media_router_webui_message_handler.cc b/chrome/browser/ui/webui/media_router/media_router_webui_message_handler.cc
index 6fe551cc3eb3bdf03ab5155bee361996b704caef..e9bfe75834b71f016b7610294556181ca351dbe4 100644
--- a/chrome/browser/ui/webui/media_router/media_router_webui_message_handler.cc
+++ b/chrome/browser/ui/webui/media_router/media_router_webui_message_handler.cc
@@ -419,6 +419,14 @@ void MediaRouterWebUIMessageHandler::OnRequestInitialData(
       cast_modes, media_router_ui_->GetPresentationRequestSourceName()));
   initial_data.Set("castModes", cast_modes_list.release());
 
+  MediaCastMode initial_cast_mode =
+      media_router_ui_->GetCastModeSelectionForCurrentHost();
+  if (initial_cast_mode != MediaCastMode::DEFAULT) {
+    initial_data.Set(

[imcheng, 2016/11/14 19:32:27]

You can use SetInteger instead which is a wrapper for Set.

[takumif, 2016/11/16 01:34:27]

Done.

+        "initialCastMode",
+        new base::FundamentalValue(static_cast<int>(initial_cast_mode)));
+  }
+
   web_ui()->CallJavascriptFunctionUnsafe(kSetInitialData, initial_data);
   media_router_ui_->UIInitialized();
 }
@@ -698,6 +706,8 @@ void MediaRouterWebUIMessageHandler::OnReportSelectedCastMode(
   }
   UMA_HISTOGRAM_SPARSE_SLOWLY("MediaRouter.Ui.Navigate.SourceSelection",
                               cast_mode_type);
+  media_router_ui_->RecordCastModeSelection(
+      static_cast<MediaCastMode>(cast_mode_type));

[imcheng, 2016/11/14 19:32:27]

Check if cast_mode_type is valid before recording.

[takumif, 2016/11/16 01:34:27]

Done.

 }
 
 void MediaRouterWebUIMessageHandler::OnReportSinkCount(