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

mojo/edk/embedder/platform_channel_pair.cc

Index: mojo/edk/embedder/platform_channel_pair.cc
diff --git a/mojo/edk/embedder/platform_channel_pair.cc b/mojo/edk/embedder/platform_channel_pair.cc
index 735ceaceb3b9a91c5705680949d72efba7ea9f14..98761deea44b855c9648ec032ea20ba45889d406 100644
--- a/mojo/edk/embedder/platform_channel_pair.cc
+++ b/mojo/edk/embedder/platform_channel_pair.cc
@@ -13,7 +13,10 @@
 #include "base/posix/global_descriptors.h"
 #include "base/strings/string_number_conversions.h"
 #include "build/build_config.h"
-#include "mojo/edk/embedder/platform_handle.h"
+#include "mojo/edk/platform/platform_handle.h"
+
+using mojo::platform::PlatformHandle;
+using mojo::platform::ScopedPlatformHandle;
 
 namespace mojo {
 namespace embedder {