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 * in the documentation and/or other materials provided with the
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 * this software without specific prior written permission.
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#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_CSS_CSS_SELECTOR_WATCH_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_CSS_CSS_SELECTOR_WATCH_H_

#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/css/style_rule.h"
#include "third_party/blink/renderer/core/dom/document.h"
#include "third_party/blink/renderer/platform/timer.h"
#include "third_party/blink/renderer/platform/wtf/hash_counted_set.h"
#include "third_party/blink/renderer/platform/wtf/hash_set.h"
#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"

namespace blink {

class CORE_EXPORT CSSSelectorWatch final
    : public GarbageCollectedFinalized<CSSSelectorWatch>,
      public Supplement<Document> {
  USING_GARBAGE_COLLECTED_MIXIN(CSSSelectorWatch);

 public:
  static const char kSupplementName[];

  explicit CSSSelectorWatch(Document&);
  virtual ~CSSSelectorWatch() = default;

  static CSSSelectorWatch& From(Document&);
  static CSSSelectorWatch* FromIfExists(Document&);

  void WatchCSSSelectors(const Vector<String>& selectors);
  const HeapVector<Member<StyleRule>>& WatchedCallbackSelectors() const {
    return watched_callback_selectors_;
  }

  void UpdateSelectorMatches(const Vector<String>& removed_selectors,
                             const Vector<String>& added_selectors);

  void Trace(blink::Visitor*) override;

 private:
  void CallbackSelectorChangeTimerFired(TimerBase*);

  HeapVector<Member<StyleRule>> watched_callback_selectors_;

  // Maps a CSS selector string with a -webkit-callback property to the number
  // of matching ComputedStyle objects in this document.
  HashCountedSet<String> matching_callback_selectors_;
  // Selectors are relative to m_matchingCallbackSelectors's contents at
  // the previous call to selectorMatchChanged.
  HashSet<String> added_selectors_;
  HashSet<String> removed_selectors_;

  TaskRunnerTimer<CSSSelectorWatch> callback_selector_change_timer_;

  // When an element is reparented, the new location's style is evaluated after
  // the expriation of the relayout timer.  We don't want to send redundant
  // callbacks to the embedder, so this counter lets us wait another time around
  // the event loop.
  int timer_expirations_;

  friend class CSSSelectorWatchTest;
};

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_CSS_CSS_SELECTOR_WATCH_H_