IntersectionObserver: remove gc-timing-revealing execeptions.

third_party/WebKit/Source/core/dom/IntersectionObservation.h

Index: third_party/WebKit/Source/core/dom/IntersectionObservation.h
diff --git a/third_party/WebKit/Source/core/dom/IntersectionObservation.h b/third_party/WebKit/Source/core/dom/IntersectionObservation.h
index 68fe73374e38b840a43947da08972b6c132a8c69..dcb93231cd50f05f279f81ac5504dec7895bad55 100644
--- a/third_party/WebKit/Source/core/dom/IntersectionObservation.h
+++ b/third_party/WebKit/Source/core/dom/IntersectionObservation.h
@@ -20,13 +20,12 @@ class IntersectionObservation final
                           Element&,
                           bool shouldReportRootBounds);
 
-  IntersectionObserver& observer() const { return *m_observer; }
+  IntersectionObserver* observer() const { return m_observer.get(); }
   Element* target() const { return m_target; }
   unsigned lastThresholdIndex() const { return m_lastThresholdIndex; }
   void setLastThresholdIndex(unsigned index) { m_lastThresholdIndex = index; }
   void computeIntersectionObservations(DOMHighResTimeStamp);
   void disconnect();
-  void clearRootAndRemoveFromTarget();
 
   DECLARE_TRACE();