ContentCapture: Reschedule task

Reschedule the current task if it waits longer than needed to run.

Bug: 1017431
Change-Id: I69f7199c9999bbe39514b1d1e5b563ffdf56d80d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1875552
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Commit-Queue: Tao Bai <michaelbai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#716444}

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

@@ -197,16 +197,13 @@ bool ContentCaptureTask::RunInternal() {
 
 void ContentCaptureTask::Run(TimerBase*) {
   TRACE_EVENT0("content_capture", "RunTask");
-  is_scheduled_ = false;
   if (!RunInternal()) {
     ScheduleInternal(ScheduleReason::kRetryTask);
   }
 }
 
 void ContentCaptureTask::ScheduleInternal(ScheduleReason reason) {
   DCHECK(local_frame_root_);
-  if (is_scheduled_)
-    return;
 
   base::TimeDelta delay;
   switch (reason) {
@@ -220,15 +217,23 @@ void ContentCaptureTask::ScheduleInternal(ScheduleReason reason) {
       break;
   }
 
+  // Return if the current task is about to run soon.
+  if (delay_task_ && delay_task_->IsActive() &&
+      delay_task_->NextFireInterval() < delay) {
+    return;
+  }
+
   if (!delay_task_) {
     scoped_refptr<base::SingleThreadTaskRunner> task_runner =
         local_frame_root_->GetTaskRunner(TaskType::kInternalContentCapture);
     delay_task_ = std::make_unique<TaskRunnerTimer<ContentCaptureTask>>(
         task_runner, this, &ContentCaptureTask::Run);
   }
 
+  if (delay_task_->IsActive())
+    delay_task_->Stop();
+
   delay_task_->StartOneShot(delay, FROM_HERE);
-  is_scheduled_ = true;
   TRACE_EVENT_INSTANT1("content_capture", "ScheduleTask",
                        TRACE_EVENT_SCOPE_THREAD, "reason", reason);
 }
@@ -252,4 +257,15 @@ void ContentCaptureTask::ClearDocumentSessionsForTesting() {
   task_session_->ClearDocumentSessionsForTesting();
 }
 
+base::TimeDelta ContentCaptureTask::GetTaskNextFireIntervalForTesting() const {
+  return delay_task_ && delay_task_->IsActive()
+             ? delay_task_->NextFireInterval()
+             : base::TimeDelta();
+}
+
+void ContentCaptureTask::CancelTaskForTesting() {
+  if (delay_task_ && delay_task_->IsActive())
+    delay_task_->Stop();
+}
+
 }  // namespace blink

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

@@ -7,6 +7,7 @@
 
 #include <memory>
 
+#include "base/time/time.h"
 #include "cc/paint/node_id.h"
 #include "third_party/blink/renderer/core/content_capture/content_capture_task_histogram_reporter.h"
 #include "third_party/blink/renderer/core/content_capture/task_session.h"
@@ -65,6 +66,9 @@ class CORE_EXPORT ContentCaptureTask : public RefCounted<ContentCaptureTask> {
 
   void ClearDocumentSessionsForTesting();
 
+  base::TimeDelta GetTaskNextFireIntervalForTesting() const;
+  void CancelTaskForTesting();
+
  protected:
   // All protected data and methods are for testing purpose.
   // Return true if the task should pause.
@@ -96,8 +100,6 @@ class CORE_EXPORT ContentCaptureTask : public RefCounted<ContentCaptureTask> {
   void ScheduleInternal(ScheduleReason reason);
   bool CaptureContent(Vector<cc::NodeId>& data);
 
-  bool is_scheduled_ = false;
-
   // Indicates if there is content change since last run.
   bool has_content_change_ = false;
 

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

@@ -520,6 +520,38 @@ TEST_F(ContentCaptureTest, TaskHistogramReporter) {
       ContentCaptureTaskHistogramReporter::kSentContentCount, 9u, 1u);
 }
 
+TEST_F(ContentCaptureTest, RescheduleTask) {
+  // This test assumes test runs much faster than task's long delay which is 5s.
+  scoped_refptr<ContentCaptureTaskTestHelper> task = GetContentCaptureTask();
+  task->CancelTaskForTesting();
+  EXPECT_TRUE(task->GetTaskNextFireIntervalForTesting().is_zero());
+  task->Schedule(ContentCaptureTask::ScheduleReason::kContentChange);
+  auto begin = base::TimeTicks::Now();
+  base::TimeDelta interval1 = task->GetTaskNextFireIntervalForTesting();
+  task->Schedule(ContentCaptureTask::ScheduleReason::kScrolling);
+  base::TimeDelta interval2 = task->GetTaskNextFireIntervalForTesting();
+  auto test_running_time = base::TimeTicks::Now() - begin;
+  // The interval1 will be greater than interval2 even the task wasn't
+  // rescheduled, removing the test_running_time from interval1 make sure
+  // task rescheduled.
+  EXPECT_GT(interval1 - test_running_time, interval2);
+}
+
+TEST_F(ContentCaptureTest, NotRescheduleTask) {
+  // This test assumes test runs much faster than task's long delay which is 5s.
+  scoped_refptr<ContentCaptureTaskTestHelper> task = GetContentCaptureTask();
+  task->CancelTaskForTesting();
+  EXPECT_TRUE(task->GetTaskNextFireIntervalForTesting().is_zero());
+  task->Schedule(ContentCaptureTask::ScheduleReason::kContentChange);
+  auto begin = base::TimeTicks::Now();
+  base::TimeDelta interval1 = task->GetTaskNextFireIntervalForTesting();
+  task->Schedule(ContentCaptureTask::ScheduleReason::kContentChange);
+  base::TimeDelta interval2 = task->GetTaskNextFireIntervalForTesting();
+  auto test_running_time = base::TimeTicks::Now() - begin;
+  EXPECT_GE(interval1, interval2);
+  EXPECT_LE(interval1 - test_running_time, interval2);
+}
+
 // TODO(michaelbai): use RenderingTest instead of PageTestBase for multiple
 // frame test.
 class ContentCaptureSimTest : public SimTest {