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diff --git a/mojo/public/cpp/bindings/lib/shared_data.h b/mojo/public/cpp/bindings/lib/shared_data.h
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+++ b/mojo/public/cpp/bindings/lib/shared_data.h
@@ -0,0 +1,81 @@
+// Copyright 2014 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 MOJO_PUBLIC_CPP_BINDINGS_LIB_SHARED_DATA_H_
+#define MOJO_PUBLIC_CPP_BINDINGS_LIB_SHARED_DATA_H_
+
+namespace mojo {
+namespace internal {
+
+// Used to allocate an instance of T that can be shared via reference counting.
+template <typename T>
+class SharedData {
+ public:
+  ~SharedData() {
+    holder_->Release();
+  }
+
+  SharedData() : holder_(new Holder()) {
+  }
+
+  explicit SharedData(const T& value) : holder_(new Holder(value)) {
+  }
+
+  SharedData(const SharedData<T>& other) : holder_(other.holder_) {
+    holder_->Retain();
+  }
+
+  SharedData<T>& operator=(const SharedData<T>& other) {
+    if (other.holder_ == holder_)
+      return *this;
+    holder_->Release();
+    holder_ = other.holder_;
+    holder_->Retain();
+  }
+
+  void reset() {
+    holder_->Release();
+    holder_ = new Holder();
+  }
+
+  void reset(const T& value) {
+    holder_->Release();
+    holder_ = new Holder(value);
+  }
+
+  void set_value(const T& value) {
+    holder_->value = value;
+  }
+  T* mutable_value() {
+    return &holder_->value;
+  }
+  const T& value() const {
+    return holder_->value;
+  }
+
+ private:
+  class Holder {
+   public:
+    Holder() : value(), ref_count_(1) {
+    }
+    Holder(const T& value) : value(value), ref_count_(1) {
+    }
+
+    void Retain() { ++ref_count_; }
+    void Release() { if (--ref_count_ == 0) delete this; }
+
+    T value;
+
+   private:
+    int ref_count_;
+    MOJO_DISALLOW_COPY_AND_ASSIGN(Holder);
+  };
+
+  Holder* holder_;
+};
+
+}  // namespace internal
+}  // namespace mojo
+
+#endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_SHARED_DATA_H_