[mojo-edk] Add support for transferring mach ports.

mojo/edk/embedder/platform_shared_buffer.cc

Index: mojo/edk/embedder/platform_shared_buffer.cc
diff --git a/mojo/edk/embedder/platform_shared_buffer.cc b/mojo/edk/embedder/platform_shared_buffer.cc
index 9516634b64cea022191ae99276ac7592959a46f2..f3f9b70bc282861a49994c87f88f95218cb49058 100644
--- a/mojo/edk/embedder/platform_shared_buffer.cc
+++ b/mojo/edk/embedder/platform_shared_buffer.cc
@@ -210,11 +210,6 @@ void PlatformSharedBuffer::InitFromSharedMemoryHandle(
     base::SharedMemoryHandle handle) {
   DCHECK(!shared_memory_);
 
-#if defined(OS_MACOSX) && !defined(OS_IOS)
-  // TODO(crbug.com/582468): Support Mach shared memory.
-  CHECK(handle.GetType() == base::SharedMemoryHandle::POSIX);
-#endif
-
   // TODO(crbug.com/556587): Support read-only handles.
   shared_memory_.reset(new base::SharedMemory(handle, false));
 }