EDK: Move {platform_handle,scoped_platform_handle}.* to //mojo/edk/platform.

mojo/edk/platform/platform_handle.h

 // Copyright 2013 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.
 
-#ifndef MOJO_EDK_EMBEDDER_PLATFORM_HANDLE_H_
-#define MOJO_EDK_EMBEDDER_PLATFORM_HANDLE_H_
+#ifndef MOJO_EDK_PLATFORM_PLATFORM_HANDLE_H_
+#define MOJO_EDK_PLATFORM_PLATFORM_HANDLE_H_
 
 namespace mojo {
-namespace embedder {
+namespace platform {
 
 // A |PlatformHandle| is just a file descriptor on POSIX.
 struct PlatformHandle {
   PlatformHandle() : fd(-1) {}
   explicit PlatformHandle(int fd) : fd(fd) {}
 
   void CloseIfNecessary();
 
   bool is_valid() const { return fd != -1; }
 
   int fd;
 };
 
-}  // namespace embedder
+}  // namespace platform
 }  // namespace mojo
 
-#endif  // MOJO_EDK_EMBEDDER_PLATFORM_HANDLE_H_
+#endif  // MOJO_EDK_PLATFORM_PLATFORM_HANDLE_H_