[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 109 matching lines @@
   // Duplicates The underlying OS primitive. Returns an invalid handle on
   // failure. The caller is responsible for destroying the duplicated OS
   // primitive.
   static SharedMemoryHandle DuplicateHandle(const SharedMemoryHandle& handle);
 
 #if defined(OS_POSIX)
   // This method requires that the SharedMemoryHandle is backed by a POSIX fd.
   static int GetFdFromSharedMemoryHandle(const SharedMemoryHandle& handle);
 #endif
 
+  int importance() const { return importance_; }
+  void set_importance(int importance) { importance_ = importance; }
+
   // Creates a shared memory object as described by the options struct.
   // Returns true on success and false on failure.
   bool Create(const SharedMemoryCreateOptions& options);
 
   // Creates and maps an anonymous shared memory segment of size size.
   // Returns true on success and false on failure.
   bool CreateAndMapAnonymous(size_t size);
 
   // Creates an anonymous shared memory segment of size size.
   // Returns true on success and false on failure.
@@ skipping 79 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
-
   // Returns the last error encountered as a result of a call to Create() or
   // Map(). Note: Currently only errors from Mac POSIX shared memory
   // implementation are fully instrumented.
   // TODO(asvitkine): Evaluate whether we want to keep this ability after
   // crbug.com/703649 is fixed and expand to all platforms or remove.
   SharedMemoryError get_last_error() const { return last_error_; }
 
  private:
 #if defined(OS_POSIX) && !defined(OS_NACL) && !defined(OS_ANDROID) && \
     (!defined(OS_MACOSX) || defined(OS_IOS))
@@ skipping 18 matching lines @@
 #endif
 
   // The OS primitive that backs the shared memory region.
   SharedMemoryHandle shm_;
 
   size_t mapped_size_ = 0;
   void* memory_ = nullptr;
   bool read_only_ = false;
   size_t requested_size_ = 0;
   SharedMemoryError last_error_ = SharedMemoryError::NO_ERRORS;
+  int importance_ = 0;
 
   DISALLOW_COPY_AND_ASSIGN(SharedMemory);
 };
 
 }  // namespace base
 
 #endif  // BASE_MEMORY_SHARED_MEMORY_H_