[Harmony Cast Dialog] Record toolbar icon and cast source metrics

Record MediaRouter.Icon.Click.Location whenever the Cast trusted area
icon is clicked.

When a media route is created, call the callback to record
MediaRouter.Source.CastingSource before calling other callbacks, so that
the MediaRouterUIBase doesn't get destroyed before we get to record.

Bug: 880624
Change-Id: Ic242cb7621886035f07f8edd96ca55b0d7b7a0a8
Reviewed-on: https://chromium-review.googlesource.com/1205992
Commit-Queue: Takumi Fujimoto <takumif@chromium.org>
Reviewed-by: Derek Cheng <imcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#588945}

chrome/browser/ui/media_router/media_router_ui_base.cc

@@ -543,6 +543,13 @@ base::Optional<RouteParameters> MediaRouterUIBase::GetRouteParameters(
                                           : url::Origin::Create(GURL());
   DVLOG(1) << "DoCreateRoute: origin: " << params.origin;
 
+  // This callback must be invoked before
+  // HandleCreateSessionRequestRouteResponse(), which closes the dialog and
+  // destroys |this|.
+  params.route_result_callbacks.push_back(
+      base::BindOnce(&MediaRouterUIBase::MaybeReportCastingSource,
+                     weak_factory_.GetWeakPtr(), cast_mode));
+
   // There are 3 cases. In cases (1) and (3) the MediaRouterUIBase will need to
   // be notified via OnRouteResponseReceived(). In case (2) the dialog will be
   // closed via HandleCreateSessionRequestRouteResponse().
@@ -576,10 +583,6 @@ base::Optional<RouteParameters> MediaRouterUIBase::GetRouteParameters(
     }
   }
 
-  params.route_result_callbacks.push_back(
-      base::BindOnce(&MediaRouterUIBase::MaybeReportCastingSource,
-                     weak_factory_.GetWeakPtr(), cast_mode));
-
   params.timeout = GetRouteRequestTimeout(cast_mode);
   CHECK(initiator_);
   params.incognito = initiator_->GetBrowserContext()->IsOffTheRecord();

chrome/browser/ui/views/media_router/cast_toolbar_button.cc

@@ -7,6 +7,7 @@
 #include "chrome/browser/media/router/media_router.h"
 #include "chrome/browser/media/router/media_router_dialog_controller.h"
 #include "chrome/browser/media/router/media_router_factory.h"
+#include "chrome/browser/media/router/media_router_metrics.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/media_router/media_router_ui_service.h"
 #include "chrome/grit/generated_resources.h"
@@ -167,6 +168,8 @@ void CastToolbarButton::ButtonPressed(views::Button* sender,
     dialog_controller->HideMediaRouterDialog();
   } else {
     dialog_controller->ShowMediaRouterDialog();
+    MediaRouterMetrics::RecordMediaRouterDialogOrigin(
+        MediaRouterDialogOpenOrigin::TOOLBAR);
   }
 }