Mojo: Move system embedder API files to mojo/system/embedder.

mojo/system/embedder/scoped_platform_handle.h

Index: mojo/system/embedder/scoped_platform_handle.h
diff --git a/mojo/system/scoped_platform_handle.h b/mojo/system/embedder/scoped_platform_handle.h
similarity index 86%
rename from mojo/system/scoped_platform_handle.h
rename to mojo/system/embedder/scoped_platform_handle.h
index 9320a82e2686469a7e3d2d151fd95fff587a212a..202871820a49f22f0c99b464ad33215a184c674b 100644
--- a/mojo/system/scoped_platform_handle.h
+++ b/mojo/system/embedder/scoped_platform_handle.h
@@ -2,12 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef MOJO_SYSTEM_SCOPED_PLATFORM_HANDLE_H_
-#define MOJO_SYSTEM_SCOPED_PLATFORM_HANDLE_H_
+#ifndef MOJO_SYSTEM_EMBEDDER_SCOPED_PLATFORM_HANDLE_H_
+#define MOJO_SYSTEM_EMBEDDER_SCOPED_PLATFORM_HANDLE_H_
 
 #include "base/compiler_specific.h"
 #include "base/move.h"
-#include "mojo/system/platform_handle.h"
+#include "mojo/system/embedder/platform_handle.h"
 #include "mojo/system/system_impl_export.h"
 
 namespace mojo {
@@ -58,4 +58,4 @@ class MOJO_SYSTEM_IMPL_EXPORT ScopedPlatformHandle {
 }  // namespace embedder
 }  // namespace mojo
 
-#endif  // MOJO_SYSTEM_SCOPED_PLATFORM_HANDLE_H_
+#endif  // MOJO_SYSTEM_EMBEDDER_SCOPED_PLATFORM_HANDLE_H_