[Display] Add display configuration update metrics

Add execution time and success metrics to
UpdateDisplayConfigurationTask.

Fixed: 1058473
Change-Id: I7cf24fd10f0f84d71b28483cb0120bb77d64aab5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2088496Reviewed-by: Stéphane Marchesin <marcheu@chromium.org>
Reviewed-by: Bailey Berro <baileyberro@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Commit-Queue: Josh Nohle <nohle@chromium.org>
Cr-Commit-Position: refs/heads/master@{#751027}

tools/metrics/histograms/histograms.xml

@@ -38491,6 +38491,27 @@ uploading your change for review.
   </summary>
 </histogram>
 
+<histogram name="DisplayManager.UpdateDisplayConfigurationTask.ExecutionTime"
+    units="ms" expires_after="2021-03-04">
+  <owner>zentaro@chromium.org</owner>
+  <owner>nohle@chromium.org</owner>
+  <summary>
+    Records the execution time to update the display configuration. Emitted when
+    the update-display-configuration task finishes, successfully or not.
+  </summary>
+</histogram>
+
+<histogram name="DisplayManager.UpdateDisplayConfigurationTask.Success"
+    enum="BooleanSuccess" expires_after="2021-03-04">
+  <owner>zentaro@chromium.org</owner>
+  <owner>nohle@chromium.org</owner>
+  <summary>
+    Records whether or not the display configuration was successfully updated.
+    Emitted when the update-display-configuration task finishes, successfully or
+    not.
+  </summary>
+</histogram>
+
 <histogram base="true" name="DisplayScheduler.ShouldNotDraw" enum="Boolean"
     expires_after="2018-11-21">
   <obsolete>

ui/display/manager/update_display_configuration_task.cc

@@ -5,6 +5,7 @@
 #include "ui/display/manager/update_display_configuration_task.h"
 
 #include "base/bind.h"
+#include "base/metrics/histogram_functions.h"
 #include "ui/display/manager/configure_displays_task.h"
 #include "ui/display/manager/display_layout_manager.h"
 #include "ui/display/manager/display_util.h"
@@ -37,6 +38,7 @@ UpdateDisplayConfigurationTask::~UpdateDisplayConfigurationTask() {
 }
 
 void UpdateDisplayConfigurationTask::Run() {
+  start_timestamp_ = base::TimeTicks::Now();
   requesting_displays_ = true;
   delegate_->GetDisplays(
       base::BindOnce(&UpdateDisplayConfigurationTask::OnDisplaysUpdated,
@@ -145,6 +147,14 @@ void UpdateDisplayConfigurationTask::OnEnableSoftwareMirroring(
 }
 
 void UpdateDisplayConfigurationTask::FinishConfiguration(bool success) {
+  DCHECK(start_timestamp_);
+  base::UmaHistogramTimes(
+      "DisplayManager.UpdateDisplayConfigurationTask.ExecutionTime",
+      base::TimeTicks::Now() - *start_timestamp_);
+  base::UmaHistogramBoolean(
+      "DisplayManager.UpdateDisplayConfigurationTask.Success", success);
+  start_timestamp_.reset();
+
   std::move(callback_).Run(success, cached_displays_,
                            cached_unassociated_displays_, new_display_state_,
                            new_power_state_);

ui/display/manager/update_display_configuration_task.h

@@ -12,6 +12,8 @@
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "base/optional.h"
+#include "base/time/time.h"
 #include "ui/display/manager/configure_displays_task.h"
 #include "ui/display/manager/display_configurator.h"
 #include "ui/display/types/native_display_observer.h"
@@ -106,6 +108,9 @@ class DISPLAY_MANAGER_EXPORT UpdateDisplayConfigurationTask
 
   std::unique_ptr<ConfigureDisplaysTask> configure_task_;
 
+  // The timestamp when Run() was called. Null if the task is not running.
+  base::Optional<base::TimeTicks> start_timestamp_;
+
   base::WeakPtrFactory<UpdateDisplayConfigurationTask> weak_ptr_factory_{this};
 
   DISALLOW_COPY_AND_ASSIGN(UpdateDisplayConfigurationTask);