[memory-infra] Add method to override importance of ownership edges

base/trace_event/memory_allocator_dump_guid.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_TRACE_EVENT_MEMORY_ALLOCATOR_DUMP_GUID_H_
 #define BASE_TRACE_EVENT_MEMORY_ALLOCATOR_DUMP_GUID_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 30 matching lines @@
 
  private:
   uint64_t guid_;
 
   // Deliberately copy-able.
 };
 
 }  // namespace trace_event
 }  // namespace base
 
+namespace std {
+
+template <>
+struct BASE_EXPORT hash<base::trace_event::MemoryAllocatorDumpGuid> {
+  size_t operator()(
+      const base::trace_event::MemoryAllocatorDumpGuid& guid) const {
+    return static_cast<size_t>(guid.ToUint64());
+  }
+};
+
+}  // namespace std
+
 #endif  // BASE_TRACE_EVENT_MEMORY_ALLOCATOR_DUMP_GUID_H_