Add GetCurrentRoutes() to MediaRouter API, ensure dialog has routes at init

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

Index: chrome/browser/ui/webui/media_router/media_router_ui.cc
diff --git a/chrome/browser/ui/webui/media_router/media_router_ui.cc b/chrome/browser/ui/webui/media_router/media_router_ui.cc
index 3374fc27a4c5285c2972b246aa0fd5e50e5f571d..a184f27b43d221062dd71ff07a9bb63011b7fdf0 100644
--- a/chrome/browser/ui/webui/media_router/media_router_ui.cc
+++ b/chrome/browser/ui/webui/media_router/media_router_ui.cc
@@ -135,29 +135,7 @@ MediaRouterUI::UIMediaRoutesObserver::~UIMediaRoutesObserver() {}
 void MediaRouterUI::UIMediaRoutesObserver::OnRoutesUpdated(
     const std::vector<MediaRoute>& routes,
     const std::vector<MediaRoute::Id>& joinable_route_ids) {
-  std::vector<MediaRoute> routes_for_display;
-  std::vector<MediaRoute::Id> joinable_route_ids_for_display;
-  for (const MediaRoute& route : routes) {
-    if (route.for_display()) {
-#ifndef NDEBUG
-      for (const MediaRoute& existing_route : routes_for_display) {
-        if (existing_route.media_sink_id() == route.media_sink_id()) {
-          DVLOG(2) << "Received another route for display with the same sink"
-                   << " id as an existing route. " << route.media_route_id()
-                   << " has the same sink id as "
-                   << existing_route.media_sink_id() << ".";
-        }
-      }
-#endif
-      if (base::ContainsValue(joinable_route_ids, route.media_route_id())) {
-        joinable_route_ids_for_display.push_back(route.media_route_id());
-      }
-
-      routes_for_display.push_back(route);
-    }
-  }
-
-  callback_.Run(routes_for_display, joinable_route_ids_for_display);
+  callback_.Run(routes, joinable_route_ids);
 }
 
 MediaRouterUI::MediaRouterUI(content::WebUI* web_ui)
@@ -297,6 +275,8 @@ void MediaRouterUI::InitCommon(content::WebContents* initiator) {
     query_result_manager_->SetSourcesForCastMode(MediaCastMode::TAB_MIRROR,
                                                  {mirroring_source}, origin);
   }
+
+  OnRoutesUpdated(router_->GetCurrentRoutes(), std::vector<MediaRoute::Id>());

[imcheng, 2016/12/01 20:06:53]

Please add a comment about why we are doing this. e.g., to ensure we have the
most recent list of routes to initialize the WebUI.

Note that there might still be some artifacts, namely the Cast/Join button (if
applicable) and sink name may show up later. This is because those depend on
query results that might arrive after the initial view is established. This is
probably fine, but please manually verify that they do show up eventually.

[imcheng, 2016/12/01 20:06:53]

On second thought you might want to call this after |cast_modes_| is initialized
since there are some computation that uses it in OnRoutesUpdated.

[takumif, 2016/12/02 19:23:23]

Done.

[takumif, 2016/12/02 19:23:23]

Done.

   UpdateCastModes();
 }
 
@@ -350,6 +330,25 @@ void MediaRouterUI::UpdateCastModes() {
   }
 }
 
+void MediaRouterUI::UpdateCurrentCastModes() {

[imcheng, 2016/12/01 20:06:53]

This should probably be renamed UpdateRouteToCastModesMapping or something
similar to avoid confusing it with UpdateCastModes. Same with
|current_cast_modes_|.

[takumif, 2016/12/02 19:23:23]

Done.

+  std::unordered_map<MediaSource::Id, MediaCastMode> available_source_map;
+  for (const auto& cast_mode : cast_modes_) {
+    for (const auto& source :
+         query_result_manager_->GetSourcesForCastMode(cast_mode)) {
+      available_source_map.insert(std::make_pair(source.id(), cast_mode));
+    }
+  }
+
+  current_cast_modes_.clear();
+  for (const auto& route : routes_) {
+    auto source_entry = available_source_map.find(route.media_source().id());
+    if (source_entry != available_source_map.end()) {
+      current_cast_modes_.insert(
+          std::make_pair(route.media_route_id(), source_entry->second));
+    }
+  }
+}
+
 void MediaRouterUI::Close() {
   ConstrainedWebDialogDelegate* delegate = GetConstrainedDelegate();
   if (delegate) {
@@ -528,25 +527,29 @@ void MediaRouterUI::SetIssue(const Issue* issue) {
 void MediaRouterUI::OnRoutesUpdated(
     const std::vector<MediaRoute>& routes,
     const std::vector<MediaRoute::Id>& joinable_route_ids) {
-  routes_ = routes;
-  joinable_route_ids_ = joinable_route_ids;
+  routes_.clear();
+  joinable_route_ids_.clear();
 
-  std::unordered_map<MediaSource::Id, MediaCastMode> available_source_map;
-  for (const auto& cast_mode : cast_modes_) {
-    for (const auto& source :
-         query_result_manager_->GetSourcesForCastMode(cast_mode)) {
-      available_source_map.insert(std::make_pair(source.id(), cast_mode));
-    }
-  }
+  for (const MediaRoute& route : routes) {
+    if (route.for_display()) {
+#ifndef NDEBUG
+      for (const MediaRoute& existing_route : routes_) {
+        if (existing_route.media_sink_id() == route.media_sink_id()) {
+          DVLOG(2) << "Received another route for display with the same sink"
+                   << " id as an existing route. " << route.media_route_id()
+                   << " has the same sink id as "
+                   << existing_route.media_sink_id() << ".";
+        }
+      }
+#endif
+      if (base::ContainsValue(joinable_route_ids, route.media_route_id())) {
+        joinable_route_ids_.push_back(route.media_route_id());
+      }
 
-  current_cast_modes_.clear();
-  for (const auto& route : routes) {
-    auto source_entry = available_source_map.find(route.media_source().id());
-    if (source_entry != available_source_map.end()) {
-      current_cast_modes_.insert(
-          std::make_pair(route.media_route_id(), source_entry->second));
+      routes_.push_back(route);
     }
   }
+  UpdateCurrentCastModes();
 
   if (ui_initialized_)
     handler_->UpdateRoutes(routes_, joinable_route_ids_, current_cast_modes_);