[tracing] Implement polling in MemoryDumpManager

base/trace_event/heap_profiler_heap_dump_writer.cc

Index: base/trace_event/heap_profiler_heap_dump_writer.cc
diff --git a/base/trace_event/heap_profiler_heap_dump_writer.cc b/base/trace_event/heap_profiler_heap_dump_writer.cc
index 1bf06dbd9763e706d2e7da4ae5933d16baf994ee..8043fff995458bb61981967a4c151c1268605453 100644
--- a/base/trace_event/heap_profiler_heap_dump_writer.cc
+++ b/base/trace_event/heap_profiler_heap_dump_writer.cc
@@ -314,8 +314,7 @@ std::unique_ptr<TracedValue> ExportHeapDump(
   internal::HeapDumpWriter writer(
       session_state.stack_frame_deduplicator(),
       session_state.type_name_deduplicator(),
-      session_state.memory_dump_config().heap_profiler_options
-          .breakdown_threshold_bytes);
+      session_state.heap_profiler_breakdown_threshold_bytes());
   return Serialize(writer.Summarize(metrics_by_context));
 }