Allow constructing {Interface,Struct}Ptr from nullptr

mojo/public/cpp/system/tests/macros_unittest.cc

 // 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.
 
 // This file tests the C++ Mojo system macros and consists of "positive" tests,
 // i.e., those verifying that things work (without compile errors, or even
 // warnings if warnings are treated as errors).
 // TODO(vtl): Maybe rename "MacrosCppTest" -> "MacrosTest" if/when this gets
 // compiled into a different binary from the C API tests.
 // TODO(vtl): Fix no-compile tests (which are all disabled; crbug.com/105388)
@@ skipping 58 matching lines @@
   double local_array[4] = {6.7, 7.8, 8.9, 9.0};
   // MSVS considers this local variable unused since MOJO_ARRAYSIZE only takes
   // the size of the type of the local and not the values itself.
   MOJO_ALLOW_UNUSED_LOCAL(local_array);
   EXPECT_EQ(4u, MOJO_ARRAYSIZE(local_array));
 }
 
 // Note: MSVS is very strict (and arguably buggy) about warnings for classes
 // defined in a local scope, so define these globally.
 class MoveOnlyInt {
-  MOJO_MOVE_ONLY_TYPE_FOR_CPP_03(MoveOnlyInt, RValue)
+  MOJO_MOVE_ONLY_TYPE(MoveOnlyInt)
 
  public:
   MoveOnlyInt() : is_set_(false), value_() {}
   explicit MoveOnlyInt(int value) : is_set_(true), value_(value) {}
   ~MoveOnlyInt() {}
 
   // Move-only constructor and operator=.
-  MoveOnlyInt(RValue other) { *this = other; }
-  MoveOnlyInt& operator=(RValue other) {
-    if (other.object != this) {
-      is_set_ = other.object->is_set_;
-      value_ = other.object->value_;
-      other.object->is_set_ = false;
+  MoveOnlyInt(MoveOnlyInt&& other) { *this = other.Pass(); }
+  MoveOnlyInt& operator=(MoveOnlyInt&& other) {
+    if (&other != this) {
+      is_set_ = other.is_set_;
+      value_ = other.value_;
+      other.is_set_ = false;
     }
     return *this;
   }
 
   int value() const {
     assert(is_set());
     return value_;
   }
   bool is_set() const { return is_set_; }
 
@@ skipping 16 matching lines @@
   EXPECT_FALSE(y.is_set());
   EXPECT_TRUE(z.is_set());
   EXPECT_EQ(123, z.value());
   z = z.Pass();
   EXPECT_TRUE(z.is_set());
   EXPECT_EQ(123, z.value());
 }
 
 }  // namespace
 }  // namespace mojo