Replace SharedMemory::UniqueID usages with SharedMemoryHandle's guid

base/memory/shared_memory.h

 // Copyright (c) 2012 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_H_
 #define BASE_MEMORY_SHARED_MEMORY_H_
 
 #include <stddef.h>
 
 #include <string>
@@ skipping 199 matching lines @@
 
   // Returns a read-only handle to this shared memory region. The caller takes
   // ownership of the handle. For POSIX handles, CHECK-fails if the region
   // wasn't Created or Opened with share_read_only=true, which is required to
   // make the handle read-only. When the handle is passed to the IPC subsystem,
   // that takes ownership of the handle. As such, it's not valid to pass the
   // sample handle to the IPC subsystem twice. Returns an invalid handle on
   // failure.
   SharedMemoryHandle GetReadOnlyHandle();
 
-#if defined(OS_POSIX) && (!defined(OS_MACOSX) || defined(OS_IOS)) && \
-    !defined(OS_NACL)
-  using UniqueId = std::pair<dev_t, ino_t>;
-
-  struct UniqueIdHash {
-    size_t operator()(const UniqueId& id) const {
-      return HashInts(id.first, id.second);
-    }
-  };
-
-  // Returns a unique ID for this shared memory's handle. Note this function may
-  // access file system and be slow.
-  bool GetUniqueId(UniqueId* id) const;
-#endif
+  // Uniques identifies the shared memory region that the underlying OS resource
+  // points to. This just returns its handler's GUID.
+  base::UnguessableToken GetGUID() const;

[erikchen, 2017/05/10 20:14:16]

Please avoid adding this method to SharedMemory - it's already available as
handle().GetGUID(), and I'd like to keep the public interface to SharedMemory as
small as possible and avoid redundancies.

[hajimehoshi, 2017/05/11 10:26:00]

Done.

 
  private:
 #if defined(OS_POSIX) && !defined(OS_NACL) && !defined(OS_ANDROID) && \
     (!defined(OS_MACOSX) || defined(OS_IOS))
   bool FilePathForMemoryName(const std::string& mem_name, FilePath* path);
 #endif
 
 #if defined(OS_WIN)
   // If true indicates this came from an external source so needs extra checks
   // before being mapped.
@@ skipping 19 matching lines @@
   void*              memory_;
   bool               read_only_;
   size_t             requested_size_;
 
   DISALLOW_COPY_AND_ASSIGN(SharedMemory);
 };
 
 }  // namespace base
 
 #endif  // BASE_MEMORY_SHARED_MEMORY_H_