ContentCapture: Add metrics for constant streaming

This patch adds one metrics to record the number of times
the task run for completing a capture.

It also replaces CaptureContentTime to CaptureContentTime2.

Bug: 1137463
Change-Id: I34199438353f14beffa20976ebafb3240fd6566f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2515143
Commit-Queue: Michael Bai <michaelbai@chromium.org>
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824081}

third_party/blink/renderer/core/content_capture/content_capture_task.cc

@@ -103,10 +103,10 @@ bool ContentCaptureTask::CaptureContent() {
   if (histogram_reporter_)
     histogram_reporter_->OnCaptureContentStarted();
   bool result = CaptureContent(buffer);
-  if (histogram_reporter_)
-    histogram_reporter_->OnCaptureContentEnded(buffer.size());
   if (!buffer.IsEmpty())
     task_session_->SetCapturedContent(buffer);
+  if (histogram_reporter_)
+    histogram_reporter_->OnCaptureContentEnded(buffer.size());
   return result;
 }
 
@@ -230,9 +230,16 @@ void ContentCaptureTask::Run(TimerBase*) {
   task_delay_->IncreaseDelayExponent();
   if (histogram_reporter_)
     histogram_reporter_->OnTaskRun();
-  if (!RunInternal()) {
+  bool completed = RunInternal();
+  if (!completed) {
     ScheduleInternal(ScheduleReason::kRetryTask);
   }
+  if (histogram_reporter_ &&
+      (completed || task_state_ == TaskState::kCaptureContent)) {
+    // The current capture session ends if the task indicates it completed or
+    // is about to capture the new changes.
+    histogram_reporter_->OnAllCapturedContentSent();
+  }
 }
 
 base::TimeDelta ContentCaptureTask::GetAndAdjustDelay(ScheduleReason reason) {

third_party/blink/renderer/core/content_capture/content_capture_task_histogram_reporter.cc

@@ -14,6 +14,7 @@ constexpr char ContentCaptureTaskHistogramReporter::kCaptureContentDelayTime[];
 constexpr char ContentCaptureTaskHistogramReporter::kSendContentTime[];
 constexpr char ContentCaptureTaskHistogramReporter::kSentContentCount[];
 constexpr char ContentCaptureTaskHistogramReporter::kTaskDelayInMs[];
+constexpr char ContentCaptureTaskHistogramReporter::kTaskRunsPerCapture[];
 
 ContentCaptureTaskHistogramReporter::ContentCaptureTaskHistogramReporter()
     : capture_content_delay_time_histogram_(kCaptureContentDelayTime,
@@ -23,7 +24,8 @@ ContentCaptureTaskHistogramReporter::ContentCaptureTaskHistogramReporter()
       capture_content_time_histogram_(kCaptureContentTime, 0, 50000, 50),
       send_content_time_histogram_(kSendContentTime, 0, 50000, 50),
       sent_content_count_histogram_(kSentContentCount, 0, 10000, 50),
-      task_delay_time_in_ms_histogram_(kTaskDelayInMs, 1, 128000, 100) {}
+      task_delay_time_in_ms_histogram_(kTaskDelayInMs, 1, 128000, 100),
+      task_runs_per_capture_histogram_(kTaskRunsPerCapture, 0, 100, 50) {}
 
 ContentCaptureTaskHistogramReporter::~ContentCaptureTaskHistogramReporter() =
     default;
@@ -47,6 +49,7 @@ void ContentCaptureTaskHistogramReporter::OnTaskRun() {
                                                        task_scheduled_time_);
     task_scheduled_time_ = base::TimeTicks();
   }
+  task_runs_per_capture_++;
 }
 
 void ContentCaptureTaskHistogramReporter::OnCaptureContentStarted() {
@@ -87,6 +90,11 @@ void ContentCaptureTaskHistogramReporter::OnSendContentEnded(
                                                  send_content_start_time_);
 }
 
+void ContentCaptureTaskHistogramReporter::OnAllCapturedContentSent() {
+  task_runs_per_capture_histogram_.Count(task_runs_per_capture_);
+  task_runs_per_capture_ = 0;
+}
+
 void ContentCaptureTaskHistogramReporter::RecordsSentContentCountPerDocument(
     size_t sent_content_count) {
   sent_content_count_histogram_.Count(sent_content_count);

third_party/blink/renderer/core/content_capture/content_capture_task_histogram_reporter.h

@@ -20,24 +20,35 @@ class CORE_EXPORT ContentCaptureTaskHistogramReporter
   static constexpr char kCaptureContentDelayTime[] =
       "ContentCapture.CaptureContentDelayTime";
   static constexpr char kCaptureContentTime[] =
-      "ContentCapture.CaptureContentTime";
+      "ContentCapture.CaptureContentTime2";
   static constexpr char kSendContentTime[] = "ContentCapture.SendContentTime";
   static constexpr char kSentContentCount[] = "ContentCapture.SentContentCount";
   static constexpr char kTaskDelayInMs[] = "ContentCapture.TaskDelayTimeInMs";
+  static constexpr char kTaskRunsPerCapture[] =
+      "ContentCapture.TaskRunsPerCapture";
 
   ContentCaptureTaskHistogramReporter();
   ~ContentCaptureTaskHistogramReporter();
 
   void OnContentChanged();
   void OnTaskScheduled(bool record_task_delay);
+  // Invoked on every task starts.
   void OnTaskRun();
+  // Invoked on a capturing session starts, a session begins with
+  // OnCaptureContentStarted(), ends with OnAllCaptureContentSent().
   void OnCaptureContentStarted();
+  // Invoked on the on-screen content captured and ready to be sent out.
   void OnCaptureContentEnded(size_t captured_content_count);
   void OnSendContentStarted();
   void OnSendContentEnded(size_t sent_content_count);
+  // Invoked on a capturing session ends, at that time, all captured changes
+  // which include the new, changed and removed content has been sent.
+  void OnAllCapturedContentSent();
   void RecordsSentContentCountPerDocument(size_t sent_content_count);
 
  private:
+  void MayRecordTaskRunsPerCapture();
+
   // The time of first content change since the last content captured.
   base::Optional<base::TimeTicks> content_change_time_;
   // The copy of |content_change_time| after the content has been captured; we
@@ -51,6 +62,9 @@ class CORE_EXPORT ContentCaptureTaskHistogramReporter
   // The time when the task is scheduled, is valid if kTaskDelayInMs needs to be
   // recorded.
   base::TimeTicks task_scheduled_time_;
+  // Counts the task run times to complete a capture which includes capturing
+  // and sending the content.
+  size_t task_runs_per_capture_ = 0;
 
   // Records time from first content change to content that has been sent, its
   // range is 500ms from to 30s.
@@ -67,6 +81,9 @@ class CORE_EXPORT ContentCaptureTaskHistogramReporter
   // 1ms to 128s. The time of task that was scheduled for the retry wasn't
   // measured because it is always 500ms.
   CustomCountHistogram task_delay_time_in_ms_histogram_;
+  // Records the number of times ContentCapture task run to complete a capture
+  // which includes capturing and sending the content.
+  CustomCountHistogram task_runs_per_capture_histogram_;
 };
 
 }  // namespace blink

third_party/blink/renderer/core/content_capture/content_capture_test.cc

@@ -642,7 +642,8 @@ TEST_P(ContentCaptureTest, TaskHistogramReporter) {
       ContentCaptureTaskHistogramReporter::kCaptureContentDelayTime, 0u);
   histograms.ExpectTotalCount(
       ContentCaptureTaskHistogramReporter::kSentContentCount, 0u);
-
+  histograms.ExpectTotalCount(
+      ContentCaptureTaskHistogramReporter::kTaskRunsPerCapture, 0u);
   histograms.ExpectTotalCount(
       ContentCaptureTaskHistogramReporter::kTaskDelayInMs, 1u);
 
@@ -695,6 +696,13 @@ TEST_P(ContentCaptureTest, TaskHistogramReporter) {
   histograms.ExpectTotalCount(
       ContentCaptureTaskHistogramReporter::kTaskDelayInMs, 1u);
 
+  histograms.ExpectTotalCount(
+      ContentCaptureTaskHistogramReporter::kTaskRunsPerCapture, 1u);
+  // Verify the task ran 4 times, first run stopped before capturing content
+  // and 2nd run captured content, 3rd and 4th run sent the content out.
+  histograms.ExpectBucketCount(
+      ContentCaptureTaskHistogramReporter::kTaskRunsPerCapture, 4u, 1u);
+
   // Create a node and run task until it stops.
   CreateTextNodeAndNotifyManager();
   GetContentCaptureTask()->SetTaskStopState(
@@ -709,6 +717,13 @@ TEST_P(ContentCaptureTest, TaskHistogramReporter) {
   histograms.ExpectTotalCount(
       ContentCaptureTaskHistogramReporter::kSentContentCount, 0u);
 
+  histograms.ExpectTotalCount(
+      ContentCaptureTaskHistogramReporter::kTaskRunsPerCapture, 2u);
+  // Verify the task ran 1 times for this session because we didn't explicitly
+  // stop it.
+  histograms.ExpectBucketCount(
+      ContentCaptureTaskHistogramReporter::kTaskRunsPerCapture, 1u, 1u);
+
   GetContentCaptureTask()->ClearDocumentSessionsForTesting();
   ThreadState::Current()->CollectAllGarbageForTesting();
   histograms.ExpectTotalCount(

tools/metrics/histograms/histograms_xml/content/histograms.xml

@@ -37,7 +37,11 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 </histogram>
 
 <histogram name="ContentCapture.CaptureContentTime" units="microseconds"
-    expires_after="2021-04-04">
+    expires_after="M87">
+  <obsolete>
+    Replaced by ContentCapture.CaptureContentTime2 since M87, the new histogram
+    records the grouping time additionally.
+  </obsolete>
   <owner>michaelbai@chromium.org</owner>
   <owner>src/third_party/blink/renderer/core/content_capture/OWNERS</owner>
   <summary>
@@ -48,6 +52,18 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
+<histogram name="ContentCapture.CaptureContentTime2" units="microseconds"
+    expires_after="2021-04-04">
+  <owner>michaelbai@chromium.org</owner>
+  <owner>src/third_party/blink/renderer/core/content_capture/OWNERS</owner>
+  <summary>
+    The time taken to capture the on-screen content and group them by document.
+
+    Note that this metrics is only recorded on clients on which a
+    high-resolution clock is available.
+  </summary>
+</histogram>
+
 <histogram name="ContentCapture.GetBoundingBox" units="microseconds"
     expires_after="2021-04-04">
   <owner>michaelbai@chromium.org</owner>
@@ -91,6 +107,18 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
+<histogram name="ContentCapture.TaskRunsPerCapture" units="runs"
+    expires_after="2021-04-04">
+  <owner>michaelbai@chromium.org</owner>
+  <owner>src/third_party/blink/renderer/core/content_capture/OWNERS</owner>
+  <summary>
+    The number of the times the task runs for a content capture session.
+
+    A content capture session begins with capturing on-screen content and ends
+    in sending all changes.
+  </summary>
+</histogram>
+
 <histogram name="ContentIndex.ContentAdded" enum="ContentIndexCategory"
     expires_after="M89">
   <owner>rayankans@chromium.org</owner>