Reland of "[heap] Tracer: Handle incremental marking scopes"

src/heap/mark-compact.cc

Index: src/heap/mark-compact.cc
diff --git a/src/heap/mark-compact.cc b/src/heap/mark-compact.cc
index e88ca8a076f86f561b66f65e951f2883e11fb2ee..db3bcff7a1e14ab93ee6f8b75002ad87930629b8 100644
--- a/src/heap/mark-compact.cc
+++ b/src/heap/mark-compact.cc
@@ -814,6 +814,7 @@ void MarkCompactCollector::Prepare() {
 
   if (!was_marked_incrementally_) {
     if (heap_->UsingEmbedderHeapTracer()) {
+      TRACE_GC(heap()->tracer(), GCTracer::Scope::MC_MARK_WRAPPER_PROLOGUE);
       heap_->mark_compact_collector()->embedder_heap_tracer()->TracePrologue();
     }
   }
@@ -2081,12 +2082,14 @@ void MarkCompactCollector::ProcessEphemeralMarking(
   bool work_to_do = true;
   while (work_to_do) {
     if (UsingEmbedderHeapTracer()) {
+      TRACE_GC(heap()->tracer(), GCTracer::Scope::MC_MARK_WRAPPER_TRACING);
       RegisterWrappersWithEmbedderHeapTracer();
       embedder_heap_tracer()->AdvanceTracing(
           0, EmbedderHeapTracer::AdvanceTracingActions(
                  EmbedderHeapTracer::ForceCompletionAction::FORCE_COMPLETION));
     }
     if (!only_process_harmony_weak_collections) {
+      TRACE_GC(heap()->tracer(), GCTracer::Scope::MC_MARK_OBJECT_GROUPING);
       isolate()->global_handles()->IterateObjectGroups(
           visitor, &IsUnmarkedHeapObjectWithHeap);
       MarkImplicitRefGroups(&MarkCompactMarkingVisitor::MarkObject);
@@ -2365,6 +2368,7 @@ void MarkCompactCollector::MarkLiveObjects() {
       TRACE_GC(heap()->tracer(), GCTracer::Scope::MC_MARK_WEAK_CLOSURE_HARMONY);
       ProcessEphemeralMarking(&root_visitor, true);
       if (UsingEmbedderHeapTracer()) {
+        TRACE_GC(heap()->tracer(), GCTracer::Scope::MC_MARK_WRAPPER_EPILOGUE);
         embedder_heap_tracer()->TraceEpilogue();
       }
     }