1 files changed, 51 insertions, 0 deletions
diff --git a/dom/base/ScrollingMetrics.h b/dom/base/ScrollingMetrics.h
new file mode 100644
index 0000000000..081c38d069
--- /dev/null
+++ b/dom/base/ScrollingMetrics.h
@@ -0,0 +1,51 @@
+/* -*- 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/. */
+
+#ifndef mozilla_dom_ScrollingMetrics_h
+#define mozilla_dom_ScrollingMetrics_h
+
+#include "Units.h"
+#include "mozilla/MozPromise.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/StaticPtr.h"
+
+namespace mozilla {
+
+/**
+ * ScrollingMetrics records user-intiated scrolling interactions. These are
+ * aggregrated along with other user interactions (e.g. typing, view time), in
+ * the history metadata.
+ */
+class ScrollingMetrics {
+ public:
+  using ScrollingMetricsPromise =
+      MozPromise<std::tuple<uint32_t, uint32_t>, bool, true>;
+
+  static RefPtr<ScrollingMetricsPromise> CollectScrollingMetrics() {
+    return GetSingleton()->CollectScrollingMetricsInternal();
+  }
+
+  // Return the tuple of <scrollingTimeInMilliseconds,
+  // ScrollingDistanceInPixels>
+  static std::tuple<uint32_t, uint32_t> CollectLocalScrollingMetrics() {
+    return GetSingleton()->CollectLocalScrollingMetricsInternal();
+  }
+
+  // Report a new user-initiated scrolling interaction
+  static void OnScrollingInteraction(CSSCoord distanceScrolled);
+
+  static void OnScrollingInteractionEnded();
+
+ private:
+  static ScrollingMetrics* GetSingleton();
+  static StaticAutoPtr<ScrollingMetrics> sSingleton;
+  RefPtr<ScrollingMetricsPromise> CollectScrollingMetricsInternal();
+  std::tuple<uint32_t, uint32_t> CollectLocalScrollingMetricsInternal();
+};
+
+}  // namespace mozilla
+
+#endif /* mozilla_dom_ScrollingMetrics_h */