Add P2 UMA metrics for Media Router user actions.

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 34eeac20cc0344724b625bf49d0fa25a22030319..54b87d095b70c4da9aaaf2450dfff0afe3612821 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
@@ -28,6 +28,8 @@ const char kCreateRoute[] = "requestRoute";
 const char kActOnIssue[] = "actOnIssue";
 const char kCloseRoute[] = "closeRoute";
 const char kCloseDialog[] = "closeDialog";
+const char kReportClickedSinkIndex[] = "reportClickedSinkIndex";
+const char kReportSelectedCastMode[] = "reportSelectedCastMode";
 const char kReportSinkCount[] = "reportSinkCount";
 const char kOnInitialDataReceived[] = "onInitialDataReceived";
 
@@ -249,6 +251,14 @@ void MediaRouterWebUIMessageHandler::RegisterMessages() {
       base::Bind(&MediaRouterWebUIMessageHandler::OnCloseDialog,
                  base::Unretained(this)));
   web_ui()->RegisterMessageCallback(
+      kReportClickedSinkIndex,
+      base::Bind(&MediaRouterWebUIMessageHandler::OnReportClickedSinkIndex,
+                 base::Unretained(this)));
+  web_ui()->RegisterMessageCallback(
+      kReportSelectedCastMode,
+      base::Bind(&MediaRouterWebUIMessageHandler::OnReportSelectedCastMode,
+                 base::Unretained(this)));
+  web_ui()->RegisterMessageCallback(
       kReportSinkCount,
       base::Bind(&MediaRouterWebUIMessageHandler::OnReportSinkCount,
                  base::Unretained(this)));
@@ -364,12 +374,17 @@ void MediaRouterWebUIMessageHandler::OnCloseRoute(
   DVLOG(1) << "OnCloseRoute";
   const base::DictionaryValue* args_dict = nullptr;
   std::string route_id;
+  bool is_local;
   if (!args->GetDictionary(0, &args_dict) ||
-      !args_dict->GetString("routeId", &route_id)) {
+      !args_dict->GetString("routeId", &route_id) ||
+      !args_dict->GetBoolean("isLocal", &is_local)) {
     DVLOG(1) << "Unable to extract args.";
     return;
   }
   media_router_ui_->CloseRoute(route_id);
+
+  int route_type = is_local ? 0 : 1;
+  UMA_HISTOGRAM_COUNTS_100("MediaRouter.Ui.Action.StopRoute", route_type);

[Ilya Sherman, 2015/12/28 23:13:00]

Please use UMA_HISTOGRAM_BOOLEAN if you're only emitting two values.

[apacible, 2015/12/29 01:21:01]

Done.

 }
 
 void MediaRouterWebUIMessageHandler::OnCloseDialog(
@@ -382,6 +397,30 @@ void MediaRouterWebUIMessageHandler::OnCloseDialog(
   media_router_ui_->Close();
 }
 
+void MediaRouterWebUIMessageHandler::OnReportClickedSinkIndex(
+    const base::ListValue* args) {
+  DVLOG(1) << "OnReportClickedSinkIndex";
+  int index;
+  if (!args->GetInteger(0, &index)) {
+    DVLOG(1) << "Unable to extract args.";
+    return;
+  }
+  UMA_HISTOGRAM_COUNTS_100("MediaRouter.Ui.Action.StartLocalPosition",
+                           index);

[Ilya Sherman, 2015/12/28 23:13:00]

Optional: It might be reasonable to use UMA_HISTOGRAM_SPARSE_SLOWLY here,
capping the logged value at some reasonable upper bound (say, 100).  This would
both (a) give you more precise counts, and (b) use less memory.

[apacible, 2015/12/29 01:21:01]

Done.

+}
+
+void MediaRouterWebUIMessageHandler::OnReportSelectedCastMode(
+    const base::ListValue* args) {
+  DVLOG(1) << "OnReportSelectedCastMode";
+  int cast_mode_type;
+  if (!args->GetInteger(0, &cast_mode_type)) {
+    DVLOG(1) << "Unable to extract args.";
+    return;
+  }
+  UMA_HISTOGRAM_COUNTS_100("MediaRouter.Ui.Navigate.SourceSelection",
+                           cast_mode_type);

[Ilya Sherman, 2015/12/28 23:13:00]

This should be either UMA_HISTOGRAM_ENUMERATION (probably preferred in this
case) or UMA_HISTOGRAM_SPARSE_SLOWLY.

[apacible, 2015/12/29 01:21:01]

Done.

+}
+
 void MediaRouterWebUIMessageHandler::OnReportSinkCount(
     const base::ListValue* args) {
   DVLOG(1) << "OnReportSinkCount";