Use per-frame WebTaskRunner with makeCancellable in AXObjectCacheImpl

third_party/WebKit/Source/modules/accessibility/AXObjectCacheImpl.h

Index: third_party/WebKit/Source/modules/accessibility/AXObjectCacheImpl.h
diff --git a/third_party/WebKit/Source/modules/accessibility/AXObjectCacheImpl.h b/third_party/WebKit/Source/modules/accessibility/AXObjectCacheImpl.h
index 7a40d61b60c3a9490e6c9615259ae6f3eb8db18e..0417f9d5d8c44c7870db152d3ae4cd3df4384b01 100644
--- a/third_party/WebKit/Source/modules/accessibility/AXObjectCacheImpl.h
+++ b/third_party/WebKit/Source/modules/accessibility/AXObjectCacheImpl.h
@@ -36,6 +36,7 @@
 #include "wtf/Forward.h"
 #include "wtf/HashMap.h"
 #include "wtf/HashSet.h"
+#include "wtf/MakeCancellable.h"
 #include <memory>
 
 namespace blink {
@@ -230,9 +231,9 @@ private:
     // its ID, we can quickly determine if it affects an aria-owns relationship.
     HashMap<String, std::unique_ptr<HashSet<AXID>>> m_idToAriaOwnersMapping;
 
-    Timer<AXObjectCacheImpl> m_notificationPostTimer;
+    WTF::ScopedFunctionCanceller m_notificationPostCanceller;
     HeapVector<std::pair<Member<AXObject>, AXNotification>> m_notificationsToPost;
-    void notificationPostTimerFired(TimerBase*);
+    void postNotificationsNow();
 
     AXObject* focusedImageMapUIElement(HTMLAreaElement*);