[heap] Do more incremental marking work in tasks.

src/heap/memory-reducer.cc

Index: src/heap/memory-reducer.cc
diff --git a/src/heap/memory-reducer.cc b/src/heap/memory-reducer.cc
index ae0776a50cdde25ce0427e97124a3db80a3254db..ba9010e7bc5d7186981fffc24aa5d61f49ee1664 100644
--- a/src/heap/memory-reducer.cc
+++ b/src/heap/memory-reducer.cc
@@ -86,7 +86,7 @@ void MemoryReducer::NotifyTimer(const Event& event) {
                         kIncrementalMarkingDelayMs;
       heap()->incremental_marking()->AdvanceIncrementalMarking(
           deadline, IncrementalMarking::NO_GC_VIA_STACK_GUARD,
-          IncrementalMarking::FORCE_COMPLETION);
+          IncrementalMarking::FORCE_COMPLETION, StepOrigin::kTask);
       heap()->FinalizeIncrementalMarkingIfComplete(
           GarbageCollectionReason::kFinalizeMarkingViaTask);
     }