Implements mojo::StrongBindingSet.

mojo/public/cpp/bindings/unique_ptr_impl_ref_traits.h

Index: mojo/public/cpp/bindings/unique_ptr_impl_ref_traits.h
diff --git a/mojo/public/cpp/bindings/unique_ptr_impl_ref_traits.h b/mojo/public/cpp/bindings/unique_ptr_impl_ref_traits.h
new file mode 100644
index 0000000000000000000000000000000000000000..f1ac097396b1775f3b821578235a602e47bf889c
--- /dev/null
+++ b/mojo/public/cpp/bindings/unique_ptr_impl_ref_traits.h
@@ -0,0 +1,22 @@
+// Copyright 2017 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_UNIQUE_PTR_IMPL_REF_TRAITS_H_
+#define MOJO_PUBLIC_CPP_BINDINGS_UNIQUE_PTR_IMPL_REF_TRAITS_H_
+
+namespace mojo {
+
+// Traits for a binding's implementation reference type.
+// This corresponds to a unique_ptr reference type.
+template <typename Interface>
+struct UniquePtrImplRefTraits {
+  using PointerType = std::unique_ptr<Interface>;
+
+  static bool IsNull(const PointerType& ptr) { return !ptr; }
+  static Interface* GetRawPointer(PointerType* ptr) { return ptr->get(); }
+};
+
+}  // namespace mojo
+
+#endif  // MOJO_PUBLIC_CPP_BINDINGS_UNIQUE_PTR_IMPL_REF_TRAITS_H_