Mojo: Add a platform interface for shared memory (embedder::PlatformSharedBuffer).

mojo/system/raw_shared_buffer_posix.cc

 // 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.
 
 #include "mojo/system/raw_shared_buffer.h"
 
 #include <stdint.h>
 #include <stdio.h>     // For |fileno()|.
 #include <sys/mman.h>  // For |mmap()|/|munmap()|.
 #include <sys/stat.h>
@@ skipping 97 matching lines @@
     LOG(ERROR) << "Shared memory file has the wrong size";
     return false;
   }
 
   // TODO(vtl): More checks?
 
   handle_ = platform_handle.Pass();
   return true;
 }
 
-scoped_ptr<RawSharedBufferMapping> RawSharedBuffer::MapImpl(size_t offset,
-                                                            size_t length) {
+scoped_ptr<embedder::PlatformSharedBufferMapping> RawSharedBuffer::MapImpl(
+    size_t offset,
+    size_t length) {
   size_t offset_rounding = offset % base::SysInfo::VMAllocationGranularity();
   size_t real_offset = offset - offset_rounding;
   size_t real_length = length + offset_rounding;
 
   // This should hold (since we checked |num_bytes| versus the maximum value of
   // |off_t| on creation, but it never hurts to be paranoid.
   DCHECK_LE(static_cast<uint64_t>(real_offset),
             static_cast<uint64_t>(std::numeric_limits<off_t>::max()));
 
   void* real_base = mmap(NULL,
                          real_length,
                          PROT_READ | PROT_WRITE,
                          MAP_SHARED,
                          handle_.get().fd,
                          static_cast<off_t>(real_offset));
   // |mmap()| should return |MAP_FAILED| (a.k.a. -1) on error. But it shouldn't
   // return null either.
   if (real_base == MAP_FAILED || !real_base) {
     PLOG(ERROR) << "mmap";
-    return scoped_ptr<RawSharedBufferMapping>();
+    return scoped_ptr<embedder::PlatformSharedBufferMapping>();
   }
 
   void* base = static_cast<char*>(real_base) + offset_rounding;
-  return make_scoped_ptr(
+  return scoped_ptr<embedder::PlatformSharedBufferMapping>(
       new RawSharedBufferMapping(base, length, real_base, real_length));
 }
 
 // RawSharedBufferMapping ------------------------------------------------------
 
 void RawSharedBufferMapping::Unmap() {
   int result = munmap(real_base_, real_length_);
   PLOG_IF(ERROR, result != 0) << "munmap";
 }
 
 }  // namespace system
 }  // namespace mojo