Add API function Dart_ZoneAllocate

runtime/vm/dart_api_impl_test.cc

Index: runtime/vm/dart_api_impl_test.cc
diff --git a/runtime/vm/dart_api_impl_test.cc b/runtime/vm/dart_api_impl_test.cc
index 14f093d2ae6bb97da35b46fbe415f63546a652fe..fd3d24b234baf1b7cf779f37a2c65f3d47fe6192 100644
--- a/runtime/vm/dart_api_impl_test.cc
+++ b/runtime/vm/dart_api_impl_test.cc
@@ -3386,10 +3386,11 @@ void NewNativePort_send123(Dart_Port dest_port_id,
   EXPECT_EQ(Dart_CObject::kNull, message->type);
 
   // Post integer value.
-  Dart_CObject response;
-  response.type = Dart_CObject::kInt32;
-  response.value.as_int32 = 123;
-  Dart_PostCObject(reply_port_id, &response);
+  Dart_CObject* response =
+      reinterpret_cast<Dart_CObject*>(Dart_ZoneAllocate(sizeof(Dart_CObject)));
+  response->type = Dart_CObject::kInt32;
+  response->value.as_int32 = 123;
+  Dart_PostCObject(reply_port_id, response);
 }
 
 
@@ -3401,10 +3402,11 @@ void NewNativePort_send321(Dart_Port dest_port_id,
   EXPECT_EQ(Dart_CObject::kNull, message->type);
 
   // Post integer value.
-  Dart_CObject response;
-  response.type = Dart_CObject::kInt32;
-  response.value.as_int32 = 321;
-  Dart_PostCObject(reply_port_id, &response);
+  Dart_CObject* response =
+      reinterpret_cast<Dart_CObject*>(Dart_ZoneAllocate(sizeof(Dart_CObject)));
+  response->type = Dart_CObject::kInt32;
+  response->value.as_int32 = 321;
+  Dart_PostCObject(reply_port_id, response);
 }