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

base/memory/shared_memory.h

Index: base/memory/shared_memory.h
diff --git a/base/memory/shared_memory.h b/base/memory/shared_memory.h
index 4b66cc6edd2c61ab12d28a00e3b0d8a53daad877..3a75149ec72b4928c7580a110372b80d09b90092 100644
--- a/base/memory/shared_memory.h
+++ b/base/memory/shared_memory.h
@@ -265,9 +265,9 @@ class BASE_EXPORT SharedMemory {
     }
   };
 
-  // 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: