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

base/memory/shared_memory_handle.cc

 // Copyright 2017 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.
 
 #include "base/memory/shared_memory_handle.h"
 
 namespace base {
 
 SharedMemoryHandle::SharedMemoryHandle(const SharedMemoryHandle& handle) =
     default;
 
 SharedMemoryHandle& SharedMemoryHandle::operator=(
     const SharedMemoryHandle& handle) = default;
 
 base::UnguessableToken SharedMemoryHandle::GetGUID() const {
   return guid_;
 }
 
 size_t SharedMemoryHandle::GetSize() const {
   return size_;
 }
 
+std::string SharedMemoryHandle::GetGUIDNameForTracing() const {
+  return "shared_memory/" + GetGUID().ToString();
+}
+
+trace_event::MemoryAllocatorDumpGuid SharedMemoryHandle::GetGUIDForTracing()
+    const {
+  auto name = GetGUIDNameForTracing();
+  if (name.empty())
+    return base::trace_event::MemoryAllocatorDumpGuid();
+  return base::trace_event::MemoryAllocatorDumpGuid(name);
+}
+
 }  // namespace base