1 files changed, 32 insertions, 1 deletions
diff --git a/chromium/third_party/blink/renderer/core/loader/long_task_detector_test.cc b/chromium/third_party/blink/renderer/core/loader/long_task_detector_test.cc
index 3384fa8ebfb..403ba452362 100644
--- a/chromium/third_party/blink/renderer/core/loader/long_task_detector_test.cc
+++ b/chromium/third_party/blink/renderer/core/loader/long_task_detector_test.cc
@@ -27,9 +27,26 @@ class TestLongTaskObserver :
     last_long_task_start = start_time;
     last_long_task_end = end_time;
   }
-};  // Anonymous namespace
+};
+
+class SelfUnregisteringObserver
+    : public GarbageCollected<SelfUnregisteringObserver>,
+      public LongTaskObserver {
+ public:
+  void OnLongTaskDetected(base::TimeTicks, base::TimeTicks) override {
+    called_ = true;
+    LongTaskDetector::Instance().UnregisterObserver(this);
+  }
+  bool IsCalled() const { return called_; }
+
+  void Reset() { called_ = false; }
+
+ private:
+  bool called_ = false;
+};
 
 }  // namespace
+
 class LongTaskDetectorTest : public testing::Test {
  public:
   // Public because it's executed on a task queue.
@@ -126,4 +143,18 @@ TEST_F(LongTaskDetectorTest, RegisterSameObserverTwice) {
             long_task_end_when_registered);
 }
 
+TEST_F(LongTaskDetectorTest, SelfUnregisteringObserver) {
+  auto* observer = MakeGarbageCollected<SelfUnregisteringObserver>();
+
+  LongTaskDetector::Instance().RegisterObserver(observer);
+  SimulateTask(LongTaskDetector::kLongTaskThreshold +
+               base::TimeDelta::FromMilliseconds(10));
+  EXPECT_TRUE(observer->IsCalled());
+  observer->Reset();
+
+  SimulateTask(LongTaskDetector::kLongTaskThreshold +
+               base::TimeDelta::FromMilliseconds(10));
+  EXPECT_FALSE(observer->IsCalled());
+}
+
 }  // namespace blink