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diff --git a/chromium/third_party/blink/renderer/core/loader/font_preload_manager.h b/chromium/third_party/blink/renderer/core/loader/font_preload_manager.h
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+// Copyright 2020 The Chromium Authors. All rights reserved.
+// 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_LOADER_FONT_PRELOAD_MANAGER_H_
+#define THIRD_PARTY_BLINK_RENDERER_CORE_LOADER_FONT_PRELOAD_MANAGER_H_
+
+#include "third_party/blink/renderer/core/core_export.h"
+#include "third_party/blink/renderer/platform/heap/handle.h"
+#include "third_party/blink/renderer/platform/timer.h"
+
+namespace blink {
+
+class Document;
+class FontResource;
+class FontFace;
+class ResourceFinishObserver;
+
+// This class monitors font preloading (via <link rel="preload"> or Font Loading
+// API) and notifies the relevant document, so that it can manage the first
+// rendering timing to work with preloaded fonts.
+// Design doc: https://bit.ly/36E8UKB
+class CORE_EXPORT FontPreloadManager final {
+  DISALLOW_NEW();
+
+ public:
+  explicit FontPreloadManager(Document&);
+  ~FontPreloadManager() = default;
+
+  FontPreloadManager(const FontPreloadManager&) = delete;
+  FontPreloadManager& operator=(const FontPreloadManager&) = delete;
+
+  bool HasPendingRenderBlockingFonts() const;
+  void WillBeginRendering();
+  bool RenderingHasBegun() const { return state_ == State::kUnblocked; }
+
+  void FontPreloadingStarted(FontResource*);
+  void FontPreloadingFinished(FontResource*, ResourceFinishObserver*);
+  void FontPreloadingDelaysRenderingTimerFired(TimerBase*);
+
+  void ImperativeFontLoadingStarted(FontFace*);
+  void ImperativeFontLoadingFinished();
+
+  // Exposed to web tests via internals.
+  void SetRenderDelayTimeoutForTest(base::TimeDelta timeout);
+
+  void Trace(Visitor* visitor);
+
+ private:
+  friend class FontPreloadManagerTest;
+
+  void DisableTimeoutForTest();
+
+  // State of font preloading before lifecycle updates begin
+  enum class State {
+    // Rendering hasn't begun. No font preloading yet.
+    kInitial,
+    // Rendering hasn't begun. There are ongoing font preloadings.
+    kLoading,
+    // Rendering hasn't begun. At least one font has been preloaded,
+    // and all font preloading so far has finished.
+    kLoaded,
+    // Rendering will begin soon or has begun. Font preloading shouldn't block
+    // rendering any more.
+    kUnblocked
+  };
+
+  void RenderBlockingFontLoadingStarted();
+  void RenderBlockingFontLoadingFinished();
+
+  Member<Document> document_;
+
+  // Need to hold strong references here, otherwise they'll be GC-ed immediately
+  // as Resource only holds weak references.
+  HeapHashSet<Member<ResourceFinishObserver>> finish_observers_;
+
+  unsigned imperative_font_loading_count_ = 0;
+
+  TaskRunnerTimer<FontPreloadManager> render_delay_timer_;
+  base::TimeDelta render_delay_timeout_;
+
+  State state_ = State::kInitial;
+
+  // TODO(xiaochengh): Do the same for fonts loaded for other reasons?
+};
+
+}  // namespace blink
+
+#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_LOADER_FONT_PRELOAD_MANAGER_H_