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diff --git a/toolkit/components/glean/bindings/private/MemoryDistribution.h b/toolkit/components/glean/bindings/private/MemoryDistribution.h
new file mode 100644
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+++ b/toolkit/components/glean/bindings/private/MemoryDistribution.h
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+/* -*- 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_glean_GleanMemoryDistribution_h
+#define mozilla_glean_GleanMemoryDistribution_h
+
+#include "mozilla/glean/bindings/DistributionData.h"
+#include "mozilla/Maybe.h"
+#include "nsIGleanMetrics.h"
+#include "nsTArray.h"
+
+namespace mozilla::glean {
+
+namespace impl {
+
+class MemoryDistributionMetric {
+ public:
+  constexpr explicit MemoryDistributionMetric(uint32_t aId) : mId(aId) {}
+
+  /*
+   * Accumulates the provided sample in the metric.
+   *
+   * @param aSample The sample to be recorded by the metric. The sample is
+   *                assumed to be in the confgured memory unit of the metric.
+   *
+   * Notes: Values bigger than 1 Terabyte (2^40 bytes) are truncated and an
+   * InvalidValue error is recorded.
+   */
+  void Accumulate(size_t aSample) const;
+
+  /**
+   * **Test-only API**
+   *
+   * Gets the currently stored value as a DistributionData.
+   *
+   * This function will attempt to await the last parent-process task (if any)
+   * writing to the the metric's storage engine before returning a value.
+   * This function will not wait for data from child processes.
+   *
+   * This doesn't clear the stored value.
+   * Parent process only. Panics in child processes.
+   *
+   * @param aPingName The (optional) name of the ping to retrieve the metric
+   *        for. Defaults to the first value in `send_in_pings`.
+   *
+   * @return value of the stored metric, or Nothing() if there is no value.
+   */
+  Result<Maybe<DistributionData>, nsCString> TestGetValue(
+      const nsACString& aPingName = nsCString()) const;
+
+ private:
+  const uint32_t mId;
+};
+}  // namespace impl
+
+class GleanMemoryDistribution final : public nsIGleanMemoryDistribution {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIGLEANMEMORYDISTRIBUTION
+
+  explicit GleanMemoryDistribution(uint64_t aId) : mMemoryDist(aId){};
+
+ private:
+  virtual ~GleanMemoryDistribution() = default;
+
+  const impl::MemoryDistributionMetric mMemoryDist;
+};
+
+}  // namespace mozilla::glean
+
+#endif /* mozilla_glean_GleanMemoryDistribution_h */