[mojo-edk] Make the Mojo EDK compile under NaCl.

mojo/edk/embedder/platform_shared_buffer.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/edk/embedder/platform_shared_buffer.h"
 
 #include <stddef.h>
+#if defined(OS_NACL)
+// For getpagesize() on NaCl.
+#include <unistd.h>
+#endif
 
 #include <utility>
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/shared_memory.h"
 #include "base/process/process_handle.h"
 #include "base/sys_info.h"
 #include "mojo/edk/embedder/platform_handle_utils.h"
 
@@ skipping 263 matching lines @@
 }
 
 size_t PlatformSharedBufferMapping::GetLength() const {
   return length_;
 }
 
 bool PlatformSharedBufferMapping::Map() {
   // Mojo shared buffers can be mapped at any offset. However,
   // base::SharedMemory must be mapped at a page boundary. So calculate what the
   // nearest whole page offset is, and build a mapping that's offset from that.
-  size_t offset_rounding = offset_ % base::SysInfo::VMAllocationGranularity();
+#if defined(OS_NACL)
+  // base::SysInfo isn't available under NaCl.
+  size_t page_size = getpagesize();
+#else
+  size_t page_size = base::SysInfo::VMAllocationGranularity();
+#endif
+  size_t offset_rounding = offset_ % page_size;
   size_t real_offset = offset_ - offset_rounding;
   size_t real_length = length_ + offset_rounding;
 
   if (!shared_memory_.MapAt(static_cast<off_t>(real_offset), real_length))
     return false;
 
   base_ = static_cast<char*>(shared_memory_.memory()) + offset_rounding;
   return true;
 }
 
 void PlatformSharedBufferMapping::Unmap() {
   shared_memory_.Unmap();
 }
 
 }  // namespace edk
 }  // namespace mojo