EDK: Remove platform_handle_utils*.

mojo/edk/platform/platform_handle.cc

Index: mojo/edk/platform/platform_handle.cc
diff --git a/mojo/edk/platform/platform_handle.cc b/mojo/edk/platform/platform_handle.cc
index 8a7c7be1b70d16eb3745e129f50932969dc49f3b..c65600e424237f6833226f2286a478e1ba3a630d 100644
--- a/mojo/edk/platform/platform_handle.cc
+++ b/mojo/edk/platform/platform_handle.cc
@@ -8,6 +8,8 @@
 #include <errno.h>
 #include <unistd.h>
 
+#include "mojo/edk/platform/scoped_platform_handle.h"
+
 namespace mojo {
 namespace platform {
 
@@ -26,5 +28,15 @@ void PlatformHandle::CloseIfNecessary() {
   fd = -1;
 }
 
+ScopedPlatformHandle PlatformHandle::Duplicate() const {
+  // This is slightly redundant, but it's good to be safe (and avoid the system
+  // call and resulting EBADF).
+  if (!is_valid())
+    return ScopedPlatformHandle();
+  // Note that |dup()| returns -1 on error (which is exactly the value we use
+  // for invalid |PlatformHandle| FDs).
+  return ScopedPlatformHandle(PlatformHandle(dup(fd)));
+}
+
 }  // namespace embedder
 }  // namespace mojo