Replace HeapListHashSet with HeapHashMap

This is part of an ongoing effort to simplify heap collections
and limit the types they can support (specifically, this CL
removes the only existing non-member usage of HeapListHashSet).

Bug: 1047147
Change-Id: I1c5de9f3a97588c22946eed03048159fd720b502
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2024896Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#736884}

third_party/blink/renderer/core/dom/scripted_animation_controller.cc

@@ -38,8 +38,24 @@
 
 namespace blink {
 
-std::pair<EventTarget*, StringImpl*> EventTargetKey(const Event* event) {
-  return std::make_pair(event->target(), event->type().Impl());
+bool ScriptedAnimationController::InsertToPerFrameEventsMap(
+    const Event* event) {
+  HashSet<const StringImpl*>& set =
+      per_frame_events_.insert(event->target(), HashSet<const StringImpl*>())
+          .stored_value->value;
+  return set.insert(event->type().Impl()).is_new_entry;
+}
+
+void ScriptedAnimationController::EraseFromPerFrameEventsMap(
+    const Event* event) {
+  EventTarget* target = event->target();
+  PerFrameEventsMap::iterator it = per_frame_events_.find(target);
+  if (it != per_frame_events_.end()) {
+    HashSet<const StringImpl*>& set = it->value;
+    set.erase(event->type().Impl());
+    if (set.IsEmpty())
+      per_frame_events_.erase(target);
+  }
 }
 
 ScriptedAnimationController::ScriptedAnimationController(Document* document)
@@ -111,7 +127,7 @@ void ScriptedAnimationController::DispatchEvents(
     HeapVector<Member<Event>> remaining;
     for (auto& event : event_queue_) {
       if (event && event->InterfaceName() == event_interface_filter) {
-        per_frame_events_.erase(EventTargetKey(event.Get()));
+        EraseFromPerFrameEventsMap(event.Get());
         events.push_back(event.Release());
       } else {
         remaining.push_back(event.Release());
@@ -241,7 +257,7 @@ void ScriptedAnimationController::EnqueueEvent(Event* event) {
 }
 
 void ScriptedAnimationController::EnqueuePerFrameEvent(Event* event) {
-  if (!per_frame_events_.insert(EventTargetKey(event)).is_new_entry)
+  if (!InsertToPerFrameEventsMap(event))
     return;
   EnqueueEvent(event);
 }

third_party/blink/renderer/core/dom/scripted_animation_controller.h

@@ -106,11 +106,15 @@ class CORE_EXPORT ScriptedAnimationController
 
   Document* GetDocument() const { return To<Document>(GetExecutionContext()); }
 
+  ALWAYS_INLINE bool InsertToPerFrameEventsMap(const Event* event);
+  ALWAYS_INLINE void EraseFromPerFrameEventsMap(const Event* event);
+
   FrameRequestCallbackCollection callback_collection_;
   Vector<base::OnceClosure> task_queue_;
   HeapVector<Member<Event>> event_queue_;
-  HeapListHashSet<std::pair<Member<const EventTarget>, const StringImpl*>>
-      per_frame_events_;
+  using PerFrameEventsMap =
+      HeapHashMap<Member<const EventTarget>, HashSet<const StringImpl*>>;
+  PerFrameEventsMap per_frame_events_;
   using MediaQueryListListeners =
       HeapListHashSet<Member<MediaQueryListListener>>;
   MediaQueryListListeners media_query_list_listeners_;

third_party/blink/renderer/platform/wtf/list_hash_set.h

@@ -246,8 +246,8 @@ class ListHashSet
   ValueType Take(ValuePeekInType);
   ValueType TakeFirst();
 
-  template <typename VisitorDispatcher>
-  void Trace(VisitorDispatcher);
+  template <typename VisitorDispatcher, typename A = AllocatorArg>
+  std::enable_if_t<A::kIsGarbageCollected> Trace(VisitorDispatcher);
 
  protected:
   typename ImplType::ValueType** GetBufferSlot() {
@@ -1203,8 +1203,9 @@ void ListHashSet<T, inlineCapacity, U, V>::DeleteAllNodes() {
 }
 
 template <typename T, size_t inlineCapacity, typename U, typename V>
-template <typename VisitorDispatcher>
-void ListHashSet<T, inlineCapacity, U, V>::Trace(VisitorDispatcher visitor) {
+template <typename VisitorDispatcher, typename A>
+std::enable_if_t<A::kIsGarbageCollected>
+ListHashSet<T, inlineCapacity, U, V>::Trace(VisitorDispatcher visitor) {
   if (visitor->ConcurrentTracingBailOut(
           {this, [](blink::Visitor* visitor, void* object) {
              reinterpret_cast<ListHashSet<T, inlineCapacity, U, V>*>(object)