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

mojo/edk/embedder/scoped_platform_handle.h

-// Copyright 2014 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_SCOPED_PLATFORM_HANDLE_H_
-#define MOJO_EDK_EMBEDDER_SCOPED_PLATFORM_HANDLE_H_
-
-#include "mojo/edk/embedder/platform_handle.h"
-#include "mojo/public/c/system/macros.h"
-#include "mojo/public/cpp/system/macros.h"
-
-namespace mojo {
-namespace embedder {
-
-// Scoper for |PlatformHandle|s, which are just file descriptors.
-class ScopedPlatformHandle {
- public:
-  ScopedPlatformHandle() {}
-  explicit ScopedPlatformHandle(PlatformHandle handle) : handle_(handle) {}
-  ~ScopedPlatformHandle() { handle_.CloseIfNecessary(); }
-
-  // Move-only constructor and operator=.
-  ScopedPlatformHandle(ScopedPlatformHandle&& other)
-      : handle_(other.release()) {}
-
-  ScopedPlatformHandle& operator=(ScopedPlatformHandle&& other) {
-    if (this != &other)
-      handle_ = other.release();
-    return *this;
-  }
-
-  const PlatformHandle& get() const { return handle_; }
-
-  void swap(ScopedPlatformHandle& other) {
-    PlatformHandle temp = handle_;
-    handle_ = other.handle_;
-    other.handle_ = temp;
-  }
-
-  PlatformHandle release() MOJO_WARN_UNUSED_RESULT {
-    PlatformHandle rv = handle_;
-    handle_ = PlatformHandle();
-    return rv;
-  }
-
-  void reset(PlatformHandle handle = PlatformHandle()) {
-    handle_.CloseIfNecessary();
-    handle_ = handle;
-  }
-
-  bool is_valid() const { return handle_.is_valid(); }
-
- private:
-  PlatformHandle handle_;
-
-  MOJO_MOVE_ONLY_TYPE(ScopedPlatformHandle);
-};
-
-}  // namespace embedder
-}  // namespace mojo
-
-#endif  // MOJO_EDK_EMBEDDER_SCOPED_PLATFORM_HANDLE_H_