[mojo-edk] Expose portable API for platform handle wrapping

mojo/edk/embedder/platform_shared_buffer.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_PLATFORM_SHARED_BUFFER_H_
 #define MOJO_EDK_EMBEDDER_PLATFORM_SHARED_BUFFER_H_
 
 #include <stddef.h>
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/shared_memory.h"
 #include "base/memory/shared_memory_handle.h"
 #include "base/synchronization/lock.h"
 #include "mojo/edk/embedder/scoped_platform_handle.h"
 #include "mojo/edk/system/system_impl_export.h"
+#include "mojo/public/c/system/types.h"
 
 namespace mojo {
 namespace edk {
 
 class PlatformSharedBufferMapping;
 
 // |PlatformSharedBuffer| is a thread-safe, ref-counted wrapper around
 // OS-specific shared memory. It has the following features:
 //   - A |PlatformSharedBuffer| simply represents a piece of shared memory that
 //     *may* be mapped and *may* be shared to another process.
@@ skipping 25 matching lines @@
       ScopedPlatformHandle rw_platform_handle,
       ScopedPlatformHandle ro_platform_handle);
 
   // Creates a shared buffer of size |num_bytes| from the existing shared memory
   // handle |handle|.
   static PlatformSharedBuffer* CreateFromSharedMemoryHandle(
       size_t num_bytes,
       bool read_only,
       base::SharedMemoryHandle handle);
 
+  // Returns a base::SharedMemoryHandle given a PlatformHandle and some
+  // associated settings.
+  static base::SharedMemoryHandle GetSharedMemoryHandleFromPlatformHandle(
+      MojoPlatformHandle platform_handle,
+      size_t size,
+      bool read_only);
+
+  // Returns a PlatformHandle from a given base::SharedMemoryHandle.
+  static PlatformHandle GetPlatformHandleFromSharedMemoryHandle(
+      base::SharedMemoryHandle memory_handle);
+
   // Gets the size of shared buffer (in number of bytes).
   size_t GetNumBytes() const;
 
   // Returns whether this shared buffer is read-only.
   bool IsReadOnly() const;
 
   // Maps (some) of the shared buffer into memory; [|offset|, |offset + length|]
   // must be contained in [0, |num_bytes|], and |length| must be at least 1.
   // Returns null on failure.
   std::unique_ptr<PlatformSharedBufferMapping> Map(size_t offset,
@@ skipping 95 matching lines @@
   // created from a duplicate handle.
   base::SharedMemory shared_memory_;
 
   DISALLOW_COPY_AND_ASSIGN(PlatformSharedBufferMapping);
 };
 
 }  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_EMBEDDER_PLATFORM_SHARED_BUFFER_H_