service worker: Remove some EmbeddedWorker* histograms.

These are obsolete by the ServiceWorker.StartTiming.* ones.

The motivation is to make further code changes easier, like removing
some of the IPC messages.

Bug: 855952
Change-Id: I8ed8266fdef1641f74011c2fa6889908c889fa0f
Reviewed-on: https://chromium-review.googlesource.com/1122676Reviewed-by: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Makoto Shimazu <shimazu@chromium.org>
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572112}

content/browser/service_worker/embedded_worker_instance.cc

@@ -569,7 +569,7 @@ void EmbeddedWorkerInstance::Start(mojom::EmbeddedWorkerStartParamsPtr params,
   DCHECK_NE(blink::mojom::kInvalidServiceWorkerVersionId,
             params->service_worker_version_id);
 
-  step_time_ = base::TimeTicks::Now();
+  auto start_time = base::TimeTicks::Now();
   status_ = EmbeddedWorkerStatus::STARTING;
   starting_phase_ = ALLOCATING_PROCESS;
   network_accessed_for_script_ = false;
@@ -588,7 +588,7 @@ void EmbeddedWorkerInstance::Start(mojom::EmbeddedWorkerStartParamsPtr params,
   client_.set_connection_error_handler(
       base::BindOnce(&EmbeddedWorkerInstance::Detach, base::Unretained(this)));
   inflight_start_task_.reset(
-      new StartTask(this, params->script_url, std::move(request), step_time_));
+      new StartTask(this, params->script_url, std::move(request), start_time));
   inflight_start_task_->Start(std::move(params), std::move(callback));
 }
 
@@ -679,12 +679,8 @@ void EmbeddedWorkerInstance::OnRegisteredToDevToolsManager(
     DCHECK(!devtools_proxy_);
     devtools_proxy_ = std::move(devtools_proxy);
   }
-  if (wait_for_debugger) {
-    // We don't measure the start time when wait_for_debugger flag is set. So
-    // we set the NULL time here.
-    step_time_ = base::TimeTicks();
+  if (wait_for_debugger)
     inflight_start_task_->set_skip_recording_startup_time();
-  }
   for (auto& observer : listener_list_)
     observer.OnRegisteredToDevToolsManager();
 }
@@ -710,14 +706,6 @@ void EmbeddedWorkerInstance::SendStartWorker(
   client_->StartWorker(std::move(params));
   registry_->BindWorkerToProcess(process_id(), embedded_worker_id());
 
-  if (!step_time_.is_null()) {
-    base::TimeDelta duration = UpdateStepTime();
-    if (inflight_start_task_->is_installed()) {
-      ServiceWorkerMetrics::RecordTimeToSendStartWorker(duration,
-                                                        start_situation_);
-    }
-  }
-
   starting_phase_ = is_script_streaming ? SCRIPT_STREAMING : SENT_START_WORKER;
   for (auto& observer : listener_list_)
     observer.OnStartWorkerMessageSent();
@@ -791,12 +779,6 @@ void EmbeddedWorkerInstance::OnThreadStarted(int thread_id) {
     return;
 
   starting_phase_ = THREAD_STARTED;
-  if (!step_time_.is_null()) {
-    base::TimeDelta duration = UpdateStepTime();
-    if (inflight_start_task_->is_installed())
-      ServiceWorkerMetrics::RecordTimeToStartThread(duration, start_situation_);
-  }
-
   thread_id_ = thread_id;
   for (auto& observer : listener_list_)
     observer.OnThreadStarted();
@@ -808,14 +790,7 @@ void EmbeddedWorkerInstance::OnScriptEvaluated(bool success) {
 
   DCHECK_EQ(EmbeddedWorkerStatus::STARTING, status_);
 
-  // Renderer side has completed evaluating the loaded worker script.
   starting_phase_ = SCRIPT_EVALUATED;
-  if (!step_time_.is_null()) {
-    base::TimeDelta duration = UpdateStepTime();
-    if (success && inflight_start_task_->is_installed())
-      ServiceWorkerMetrics::RecordTimeToEvaluateScript(duration,
-                                                       start_situation_);
-  }
 
   base::WeakPtr<EmbeddedWorkerInstance> weak_this = weak_factory_.GetWeakPtr();
   StartTask::RunStartCallback(
@@ -971,15 +946,6 @@ void EmbeddedWorkerInstance::OnStartFailed(
   }
 }
 
-base::TimeDelta EmbeddedWorkerInstance::UpdateStepTime() {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  DCHECK(!step_time_.is_null());
-  base::TimeTicks now = base::TimeTicks::Now();
-  base::TimeDelta duration = now - step_time_;
-  step_time_ = now;
-  return duration;
-}
-
 void EmbeddedWorkerInstance::AddMessageToConsole(
     blink::WebConsoleMessage::Level level,
     const std::string& message) {

content/browser/service_worker/embedded_worker_instance.h

@@ -281,10 +281,6 @@ class CONTENT_EXPORT EmbeddedWorkerInstance
   void OnStartFailed(StatusCallback callback,
                      blink::ServiceWorkerStatusCode status);
 
-  // Returns the time elapsed since |step_time_| and updates |step_time_|
-  // to the current time.
-  base::TimeDelta UpdateStepTime();
-
   base::WeakPtr<ServiceWorkerContextCore> context_;
   scoped_refptr<EmbeddedWorkerRegistry> registry_;
   ServiceWorkerVersion* owner_version_;
@@ -327,9 +323,6 @@ class CONTENT_EXPORT EmbeddedWorkerInstance
   ServiceWorkerMetrics::StartSituation start_situation_ =
       ServiceWorkerMetrics::StartSituation::UNKNOWN;
 
-  // Used for UMA. The start time of the current start sequence step.
-  base::TimeTicks step_time_;
-
   std::unique_ptr<ServiceWorkerContentSettingsProxyImpl> content_settings_;
   base::WeakPtrFactory<EmbeddedWorkerInstance> weak_factory_;
 

content/browser/service_worker/service_worker_metrics.cc

@@ -726,32 +726,6 @@ void ServiceWorkerMetrics::RecordProcessCreated(bool is_new_process) {
                         is_new_process);
 }
 
-void ServiceWorkerMetrics::RecordTimeToSendStartWorker(
-    base::TimeDelta duration,
-    StartSituation situation) {
-  std::string name = "EmbeddedWorkerInstance.Start.TimeToSendStartWorker";
-  UMA_HISTOGRAM_MEDIUM_TIMES(name, duration);
-  RecordSuffixedMediumTimeHistogram(
-      name, StartSituationToDeprecatedSuffix(situation), duration);
-}
-
-void ServiceWorkerMetrics::RecordTimeToStartThread(base::TimeDelta duration,
-                                                   StartSituation situation) {
-  std::string name = "EmbeddedWorkerInstance.Start.TimeToStartThread";
-  UMA_HISTOGRAM_MEDIUM_TIMES(name, duration);
-  RecordSuffixedMediumTimeHistogram(
-      name, StartSituationToDeprecatedSuffix(situation), duration);
-}
-
-void ServiceWorkerMetrics::RecordTimeToEvaluateScript(
-    base::TimeDelta duration,
-    StartSituation situation) {
-  std::string name = "EmbeddedWorkerInstance.Start.TimeToEvaluateScript";
-  UMA_HISTOGRAM_MEDIUM_TIMES(name, duration);
-  RecordSuffixedMediumTimeHistogram(
-      name, StartSituationToDeprecatedSuffix(situation), duration);
-}
-
 void ServiceWorkerMetrics::RecordStartWorkerTiming(const StartTimes& times,
                                                    StartSituation situation) {
   // Bail if the timings across processes weren't consistent.

content/browser/service_worker/service_worker_metrics.h

@@ -389,21 +389,7 @@ class ServiceWorkerMetrics {
   static void RecordFallbackedRequestMode(
       network::mojom::FetchRequestMode mode);
 
-  // Called at the beginning of each ServiceWorkerVersion::Dispatch*Event
-  // function. Records the time elapsed since idle (generally the time since the
-  // previous event ended).
-  static void RecordTimeBetweenEvents(base::TimeDelta time);
-
-  // The following record steps of EmbeddedWorkerInstance's start sequence.
-  // TODO(crbug.com/855952): Remove most of these and replace with
-  // RecordStartWorkingTiming().
   static void RecordProcessCreated(bool is_new_process);
-  static void RecordTimeToSendStartWorker(base::TimeDelta duration,
-                                          StartSituation start_situation);
-  static void RecordTimeToStartThread(base::TimeDelta duration,
-                                      StartSituation start_situation);
-  static void RecordTimeToEvaluateScript(base::TimeDelta duration,
-                                         StartSituation start_situation);
 
   CONTENT_EXPORT static void RecordStartWorkerTiming(const StartTimes& times,
                                                      StartSituation situation);

tools/metrics/histograms/histograms.xml

@@ -21981,6 +21981,10 @@ uploading your change for review.
 </histogram>
 
 <histogram name="EmbeddedWorkerInstance.Start.TimeToEvaluateScript" units="ms">
+  <obsolete>
+    Removed July 2018 (M69). Replaced with
+    ServiceWorker.StartTiming.ScriptEvaluationStartToScriptEvaluationEnd.
+  </obsolete>
   <owner>falken@chromium.org</owner>
   <summary>
     The time taken for initial evaluation of the service worker script.
@@ -22027,6 +22031,10 @@ uploading your change for review.
 </histogram>
 
 <histogram name="EmbeddedWorkerInstance.Start.TimeToSendStartWorker" units="ms">
+  <obsolete>
+    Removed July 2018 (M69). Replaced with
+    ServiceWorker.StartTiming.StartToSentStartWorker.
+  </obsolete>
   <owner>falken@chromium.org</owner>
   <summary>
     The time taken between deciding to start a worker and sending the start
@@ -22035,6 +22043,10 @@ uploading your change for review.
 </histogram>
 
 <histogram name="EmbeddedWorkerInstance.Start.TimeToStartThread" units="ms">
+  <obsolete>
+    Removed July 2018 (M69). Replaced with
+    ServiceWorker.StartTiming.ReceivedStartWorkerToScriptEvaluationStart.
+  </obsolete>
   <owner>falken@chromium.org</owner>
   <summary>
     The time taken to start the service worker thread. Specifically, the time