Pass file Regions along with FDs to child processes on Android

base/files/memory_mapped_file.h

 // Copyright 2013 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 BASE_FILES_MEMORY_MAPPED_FILE_H_
 #define BASE_FILES_MEMORY_MAPPED_FILE_H_
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/files/file.h"
@@ skipping 10 matching lines @@
 class BASE_EXPORT MemoryMappedFile {
  public:
   // The default constructor sets all members to invalid/null values.
   MemoryMappedFile();
   ~MemoryMappedFile();
 
   // Used to hold information about a region [offset + size] of a file.
   struct BASE_EXPORT Region {
     static const Region kWholeFile;
 
+    Region();
     Region(int64 offset, int64 size);
 
     bool operator==(const Region& other) const;
+    bool operator!=(const Region& other) const;
 
     // Start of the region (measured in bytes from the beginning of the file).
     int64 offset;
 
     // Length of the region in bytes.
     int64 size;
 
    private:
-    // This ctor is used only by kWholeFile, to construct a zero-sized Region
-    // (which is forbidden by the public ctor) and uniquely identify kWholeFile.
+    // Used by kWholeFile.
     Region(base::LinkerInitialized);
   };
 
   // Opens an existing file and maps it into memory. Access is restricted to
   // read only. If this object already points to a valid memory mapped file
   // then this method will fail and return false. If it cannot open the file,
   // the file does not exist, or the memory mapping fails, it will return false.
   // Later we may want to allow the user to specify access.
   bool Initialize(const FilePath& file_name);
 
@@ skipping 44 matching lines @@
   win::ScopedHandle file_mapping_;
   bool image_;  // Map as an image.
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(MemoryMappedFile);
 };
 
 }  // namespace base
 
 #endif  // BASE_FILES_MEMORY_MAPPED_FILE_H_