Allow constructing {Interface,Struct}Ptr from nullptr

mojo/public/cpp/bindings/lib/filter_chain.h

Index: mojo/public/cpp/bindings/lib/filter_chain.h
diff --git a/mojo/public/cpp/bindings/lib/filter_chain.h b/mojo/public/cpp/bindings/lib/filter_chain.h
index fc6664266a78f242aab0f104ccefa2fca9423ceb..bd7f9f54bf0116d3fd3e60d6f7da9efed55fdd7f 100644
--- a/mojo/public/cpp/bindings/lib/filter_chain.h
+++ b/mojo/public/cpp/bindings/lib/filter_chain.h
@@ -15,17 +15,15 @@ namespace mojo {
 namespace internal {
 
 class FilterChain {
-  MOJO_MOVE_ONLY_TYPE_FOR_CPP_03(FilterChain, RValue)
+  MOJO_MOVE_ONLY_TYPE(FilterChain)
 
  public:
   // Doesn't take ownership of |sink|. Therefore |sink| has to stay alive while
   // this object is alive.
   explicit FilterChain(MessageReceiver* sink = nullptr);
 
-  // Move-only constructor and operator=.
-  FilterChain(RValue other);
-  FilterChain& operator=(RValue other);
-
+  FilterChain(FilterChain&& other);
+  FilterChain& operator=(FilterChain&& other);
   ~FilterChain();
 
   template <typename FilterType>