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

mojo/edk/embedder/simple_platform_support.h

Index: mojo/edk/embedder/simple_platform_support.h
diff --git a/mojo/edk/embedder/simple_platform_support.h b/mojo/edk/embedder/simple_platform_support.h
index 41c16024167a3955e40ba4e16ed5d75c856a7ffa..d348be9851cdde25cacb768f10454845197f4717 100644
--- a/mojo/edk/embedder/simple_platform_support.h
+++ b/mojo/edk/embedder/simple_platform_support.h
@@ -27,7 +27,7 @@ class SimplePlatformSupport final : public PlatformSupport {
       size_t num_bytes) override;
   util::RefPtr<PlatformSharedBuffer> CreateSharedBufferFromHandle(
       size_t num_bytes,
-      ScopedPlatformHandle platform_handle) override;
+      platform::ScopedPlatformHandle platform_handle) override;
 
  private:
   MOJO_DISALLOW_COPY_AND_ASSIGN(SimplePlatformSupport);