[WIP] Add SharedMemoryTracker to dump base::SharedMemory usage

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 247 matching lines @@
 #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
+  // Returns a unique ID for the shared memory |handle|. Note this function may
   // access file system and be slow.
-  bool GetUniqueId(UniqueId* id) const;
+  static bool GetUniqueId(const SharedMemoryHandle& handle, UniqueId* id);
 #endif
 
  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
 
   enum ShareMode {
     SHARE_READONLY,
@@ skipping 32 matching lines @@
   void*              memory_;
   bool               read_only_;
   size_t             requested_size_;
 
   DISALLOW_COPY_AND_ASSIGN(SharedMemory);
 };
 
 }  // namespace base
 
 #endif  // BASE_MEMORY_SHARED_MEMORY_H_