Get rid of base::SharedMemory::NULLHandle();

base/memory/shared_memory_handle.h

 // Copyright 2015 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_MEMORY_SHARED_MEMORY_HANDLE_H_
 #define BASE_MEMORY_SHARED_MEMORY_HANDLE_H_
 
 #include <stddef.h>
 
 #include "build/build_config.h"
@@ skipping 65 matching lines @@
   // Makes a Mach-based SharedMemoryHandle of the given size. On error,
   // subsequent calls to IsValid() return false.
   explicit SharedMemoryHandle(mach_vm_size_t size);
 
   // Makes a Mach-based SharedMemoryHandle from |memory_object|, a named entry
   // in the task with process id |pid|. The memory region has size |size|.
   SharedMemoryHandle(mach_port_t memory_object,
                      mach_vm_size_t size,
                      base::ProcessId pid);
 
-  // Comparison operators.
-  bool operator==(const SharedMemoryHandle& handle) const;
-  bool operator!=(const SharedMemoryHandle& handle) const;
-
   // Duplicates the underlying OS resources.
   SharedMemoryHandle Duplicate() const;
 
   // Exposed so that the SharedMemoryHandle can be transported between
   // processes.
   mach_port_t GetMemoryObject() const;
 
   // Returns false on a failure to determine the size. On success, populates the
   // output variable |size|.
   bool GetSize(size_t* size) const;
 
   // The SharedMemoryHandle must be valid.
   // Returns whether the SharedMemoryHandle was successfully mapped into memory.
   // On success, |memory| is an output variable that contains the start of the
   // mapped memory.
   bool MapAt(off_t offset, size_t bytes, void** memory, bool read_only);
 #elif defined(OS_WIN)
   SharedMemoryHandle(HANDLE h, base::ProcessId pid);
 
-  // Comparison operators.
-  bool operator==(const SharedMemoryHandle& handle) const;
-  bool operator!=(const SharedMemoryHandle& handle) const;
-
   // Whether |pid_| is the same as the current process's id.
   bool BelongsToCurrentProcess() const;
 
   // Whether handle_ needs to be duplicated into the destination process when
   // an instance of this class is passed over a Chrome IPC channel.
   bool NeedsBrokering() const;
 
   HANDLE GetHandle() const;
   base::ProcessId GetPID() const;
 #else
@@ skipping 67 matching lines @@
   // Defaults to |false|.
   bool ownership_passes_to_ipc_;
 #else
   FileDescriptor file_descriptor_;
 #endif
 };
 
 }  // namespace base
 
 #endif  // BASE_MEMORY_SHARED_MEMORY_HANDLE_H_