Log the result of loading a profile for notifications

This adds a UMA metric to track if loading the profile from a
notification action is successful or not. Only logged when we're using a
system notification bridge, so not on Chrome OS and not when we use
Chrome's own notifications.

Bug: None
Change-Id: Ibb357b3036134b8f558a838c85777e2a8cc8a48f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2776011
Commit-Queue: Richard Knoll <knollr@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Cr-Commit-Position: refs/heads/master@{#865300}

chrome/browser/notifications/notification_display_service_impl.cc

@@ -9,6 +9,7 @@
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/logging.h"
+#include "base/metrics/histogram_functions.h"
 #include "build/build_config.h"
 #include "build/buildflag.h"
 #include "build/chromeos_buildflags.h"
@@ -276,9 +277,9 @@ void NotificationDisplayServiceImpl::ProfileLoadedCallback(
     const base::Optional<std::u16string>& reply,
     const base::Optional<bool>& by_user,
     Profile* profile) {
+  base::UmaHistogramBoolean("Notifications.LoadProfileResult",
+                            profile != nullptr);
   if (!profile) {
-    // TODO(miguelg): Add UMA for this condition.
-    // Perhaps propagate this through PersistentNotificationStatus.
     LOG(WARNING) << "Profile not loaded correctly";
     return;
   }

tools/metrics/histograms/histograms_xml/notifications/histograms.xml

@@ -406,6 +406,18 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
+<histogram name="Notifications.LoadProfileResult" enum="BooleanSuccess"
+    expires_after="M96">
+  <owner>knollr@chromium.org</owner>
+  <owner>peter@chromium.org</owner>
+  <summary>
+    Records the result of loading the profile when forwarding a notification
+    event. Logged on each notification action (click, close, settings, disable)
+    on platforms that use system notifications (not on Chrome OS or when we're
+    using Chrome's notifications).
+  </summary>
+</histogram>
+
 <histogram name="Notifications.macOS.ActionReceived.{Style}"
     enum="BooleanValid" expires_after="M96">
   <owner>knollr@chromium.org</owner>