memory-infra: Add a struct to carry memory use information

base/trace_event/memory_dump_request_args.cc

Index: base/trace_event/memory_dump_request_args.cc
diff --git a/base/trace_event/memory_dump_request_args.cc b/base/trace_event/memory_dump_request_args.cc
index bf72bef5e4dfca0f9ab6c8d06a230de0466bbd6b..f2744007d7e27086101906832b76f2a442a2c67e 100644
--- a/base/trace_event/memory_dump_request_args.cc
+++ b/base/trace_event/memory_dump_request_args.cc
@@ -60,5 +60,9 @@ MemoryDumpLevelOfDetail StringToMemoryDumpLevelOfDetail(
   return MemoryDumpLevelOfDetail::LAST;
 }
 
+MemoryDumpCallbackResult::MemoryDumpCallbackResult() {}
+
+MemoryDumpCallbackResult::~MemoryDumpCallbackResult() {}
+
 }  // namespace trace_event
 }  // namespace base