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

mojo/edk/embedder/BUILD.gn

Index: mojo/edk/embedder/BUILD.gn
diff --git a/mojo/edk/embedder/BUILD.gn b/mojo/edk/embedder/BUILD.gn
index b651dfe5b355c3f316818995c52342c48fc45a32..8cbadecb881c2a88d5aaa3504aca196ce00b24ee 100644
--- a/mojo/edk/embedder/BUILD.gn
+++ b/mojo/edk/embedder/BUILD.gn
@@ -56,13 +56,10 @@ mojo_edk_source_set("platform") {
     "platform_channel_pair.h",
     "platform_channel_utils.cc",
     "platform_channel_utils.h",
-    "platform_handle.cc",
-    "platform_handle.h",
     "platform_handle_utils.h",
     "platform_handle_utils_posix.cc",
     "platform_shared_buffer.h",
     "platform_support.h",
-    "scoped_platform_handle.h",
     "simple_platform_shared_buffer.cc",
     "simple_platform_shared_buffer.h",
     "simple_platform_support.cc",
@@ -71,6 +68,8 @@ mojo_edk_source_set("platform") {
 
   mojo_sdk_public_deps = [ "mojo/public/cpp/system" ]
 
+  mojo_edk_public_deps = [ "mojo/edk/platform" ]
+
   deps = [
     "//base",
   ]