1 files changed, 75 insertions, 0 deletions
diff --git a/layout/style/PreloadedStyleSheet.h b/layout/style/PreloadedStyleSheet.h
new file mode 100644
index 0000000000..e201d76daf
--- /dev/null
+++ b/layout/style/PreloadedStyleSheet.h
@@ -0,0 +1,75 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* a CSS style sheet returned from nsIStyleSheetService.preloadSheet */
+
+#ifndef mozilla_PreloadedStyleSheet_h
+#define mozilla_PreloadedStyleSheet_h
+
+#include "mozilla/css/SheetParsingMode.h"
+#include "mozilla/NotNull.h"
+#include "mozilla/Result.h"
+#include "nsCOMPtr.h"
+#include "nsCycleCollectionParticipant.h"
+#include "nsICSSLoaderObserver.h"
+#include "nsIPreloadedStyleSheet.h"
+
+class nsIURI;
+
+namespace mozilla {
+namespace dom {
+class Promise;
+}
+
+class StyleSheet;
+
+class PreloadedStyleSheet : public nsIPreloadedStyleSheet {
+ public:
+  PreloadedStyleSheet(nsIURI*, css::SheetParsingMode);
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_CLASS(PreloadedStyleSheet)
+
+  // *aResult is not addrefed, since the PreloadedStyleSheet holds a strong
+  // reference to the sheet.
+  nsresult GetSheet(StyleSheet** aResult);
+
+  nsresult Preload();
+  nsresult PreloadAsync(NotNull<dom::Promise*> aPromise);
+
+ protected:
+  virtual ~PreloadedStyleSheet() = default;
+
+ private:
+  class StylesheetPreloadObserver final : public nsICSSLoaderObserver {
+   public:
+    NS_DECL_ISUPPORTS
+
+    explicit StylesheetPreloadObserver(NotNull<dom::Promise*> aPromise,
+                                       PreloadedStyleSheet* aSheet)
+        : mPromise(aPromise), mPreloadedSheet(aSheet) {}
+
+    NS_IMETHOD StyleSheetLoaded(StyleSheet* aSheet, bool aWasDeferred,
+                                nsresult aStatus) override;
+
+   protected:
+    virtual ~StylesheetPreloadObserver() = default;
+
+   private:
+    RefPtr<dom::Promise> mPromise;
+    RefPtr<PreloadedStyleSheet> mPreloadedSheet;
+  };
+
+  RefPtr<StyleSheet> mSheet;
+
+  bool mLoaded;
+  nsCOMPtr<nsIURI> mURI;
+  css::SheetParsingMode mParsingMode;
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_PreloadedStyleSheet_h