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// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_TIMING_LAYOUT_SHIFT_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_TIMING_LAYOUT_SHIFT_H_
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/dom/dom_high_res_time_stamp.h"
#include "third_party/blink/renderer/core/timing/layout_shift_attribution.h"
#include "third_party/blink/renderer/core/timing/performance_entry.h"
#include "third_party/blink/renderer/platform/heap/collection_support/heap_vector.h"
#include "third_party/blink/renderer/platform/wtf/casting.h"
namespace blink {
// Exposes the layout shift score of an animation frame, computed as described
// in http://bit.ly/lsm-explainer.
class CORE_EXPORT LayoutShift final : public PerformanceEntry {
DEFINE_WRAPPERTYPEINFO();
public:
// Maximum number of attributions (shifted elements) to record in any single
// animation frame.
static constexpr int kMaxAttributions = 5;
typedef HeapVector<Member<LayoutShiftAttribution>, kMaxAttributions>
AttributionList;
static LayoutShift* Create(double start_time,
double value,
bool input_detected,
double input_timestamp,
AttributionList sources,
DOMWindow* source);
explicit LayoutShift(double start_time,
double value,
bool input_detected,
double input_timestamp,
AttributionList sources,
DOMWindow* source);
~LayoutShift() override;
const AtomicString& entryType() const override;
PerformanceEntryType EntryTypeEnum() const override;
double value() const { return value_; }
bool hadRecentInput() const { return had_recent_input_; }
double lastInputTime() const { return most_recent_input_timestamp_; }
const AttributionList& sources() const { return sources_; }
void Trace(Visitor*) const override;
private:
void BuildJSONValue(V8ObjectBuilder&) const override;
double value_;
bool had_recent_input_;
DOMHighResTimeStamp most_recent_input_timestamp_;
AttributionList sources_;
};
template <>
struct DowncastTraits<LayoutShift> {
static bool AllowFrom(const PerformanceEntry& entry) {
return entry.EntryTypeEnum() == PerformanceEntry::EntryType::kLayoutShift;
}
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_CORE_TIMING_LAYOUT_SHIFT_H_
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