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

base/memory/shared_memory_handle.cc

Index: base/memory/shared_memory_handle.cc
diff --git a/base/memory/shared_memory_handle.cc b/base/memory/shared_memory_handle.cc
index 085bde46c295d502f6bc78012923308ba1c3045c..4420cf4f271332bdbde09fe3f10032beed131da1 100644
--- a/base/memory/shared_memory_handle.cc
+++ b/base/memory/shared_memory_handle.cc
@@ -20,4 +20,16 @@ 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