Update the pop-up implementation to match hint/auto resolutions

See the set of behaviors described here:

  openui/open-ui#525 (comment)

which were resolved here:

  openui/open-ui#525 (comment)

This CL implements those changes in behavior, which mostly deal with
how popup=auto and popup=hint interact, and some small changes to how
`defaultopen` works.

Bug: 1307772
Change-Id: I4d280b60e7c341b4d0f97fe82e60134ff4a6e1fa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3742105
Auto-Submit: Mason Freed <masonf@chromium.org>
Reviewed-by: Joey Arhar <jarhar@chromium.org>
Commit-Queue: Mason Freed <masonf@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1021327}
NOKEYCHECK=True
GitOrigin-RevId: 033ae102a356d906af6f62d3a31588f0b2fc4b18

blink/renderer/core/dom/document.cc

@@ -7260,12 +7260,12 @@ HTMLDialogElement* Document::ActiveModalDialog() const {
   return nullptr;
 }
 
-bool Document::PopupOrHintShowing() const {
-  return !popup_and_hint_stack_.IsEmpty();
-}
-bool Document::HintShowing() const {
-  return !popup_and_hint_stack_.IsEmpty() &&
-         (popup_and_hint_stack_.back()->PopupType() == PopupValueType::kHint);
+Element* Document::TopmostPopupAutoOrHint() const {
+  if (PopupHintShowing())
+    return PopupHintShowing();
+  if (PopupStack().IsEmpty())
+    return nullptr;
+  return PopupStack().back();
 }
 
 void Document::exitPointerLock() {
@@ -8019,7 +8019,8 @@ void Document::Trace(Visitor* visitor) const {
   visitor->Trace(lists_invalidated_at_document_);
   visitor->Trace(node_lists_);
   visitor->Trace(top_layer_elements_);
-  visitor->Trace(popup_and_hint_stack_);
+  visitor->Trace(popup_hint_showing_);
+  visitor->Trace(popup_stack_);
   visitor->Trace(popups_waiting_to_hide_);
   visitor->Trace(load_event_delay_timer_);
   visitor->Trace(plugin_loading_timer_);

blink/renderer/core/dom/document.h

@@ -73,6 +73,7 @@
 #include "third_party/blink/renderer/platform/heap/collection_support/heap_hash_map.h"
 #include "third_party/blink/renderer/platform/heap/collection_support/heap_hash_set.h"
 #include "third_party/blink/renderer/platform/heap/collection_support/heap_linked_hash_set.h"
+#include "third_party/blink/renderer/platform/heap/collection_support/heap_vector.h"
 #include "third_party/blink/renderer/platform/heap_observer_set.h"
 #include "third_party/blink/renderer/platform/instrumentation/use_counter.h"
 #include "third_party/blink/renderer/platform/scheduler/public/post_cancellable_task.h"
@@ -1515,14 +1516,15 @@ class CORE_EXPORT Document : public ContainerNode,
 
   HTMLDialogElement* ActiveModalDialog() const;
 
-  HeapVector<Member<Element>>& PopupAndHintStack() {
-    return popup_and_hint_stack_;
-  }
+  Element* PopupHintShowing() const { return popup_hint_showing_; }
+  void SetPopupHintShowing(Element* element) { popup_hint_showing_ = element; }
+  HeapVector<Member<Element>>& PopupStack() { return popup_stack_; }
+  const HeapVector<Member<Element>>& PopupStack() const { return popup_stack_; }
+  bool PopupAutoShowing() const { return !popup_stack_.IsEmpty(); }
+  Element* TopmostPopupAutoOrHint() const;
   HeapHashSet<Member<Element>>& PopupsWaitingToHide() {
     return popups_waiting_to_hide_;
   }
-  bool PopupOrHintShowing() const;
-  bool HintShowing() const;
 
   // A non-null template_document_host_ implies that |this| was created by
   // EnsureTemplateDocument().
@@ -2318,12 +2320,11 @@ class CORE_EXPORT Document : public ContainerNode,
   // stack and is thus the one that will be visually on top.
   HeapVector<Member<Element>> top_layer_elements_;
 
-  // The stack of currently-displayed Popup (and Hint) elements, which are
-  // elements that have either `popup=popup` or `popup=hint`. Elements in the
-  // stack go from earliest (bottom-most) to latest (top-most). If there is a
-  // hint in the stack, it is at the top.
-  HeapVector<Member<Element>> popup_and_hint_stack_;
-
+  // The stack of currently-displayed `popup=auto` elements. Elements in the
+  // stack go from earliest (bottom-most) to latest (top-most).
+  HeapVector<Member<Element>> popup_stack_;
+  // The `popup=hint` that is currently showing, if any.
+  Member<Element> popup_hint_showing_;
   // A set of popups for which hidePopUp() has been called, but animations are
   // still running.
   HeapHashSet<Member<Element>> popups_waiting_to_hide_;