GC: Refactor public incremental marking interface in heap

src/heap/heap.h

Index: src/heap/heap.h
diff --git a/src/heap/heap.h b/src/heap/heap.h
index 54dfc7ae1a26da7fb32d5f3922da73012a72102a..feb3c87dba46d373ae39e6d31868b17dfabcf4e7 100644
--- a/src/heap/heap.h
+++ b/src/heap/heap.h
@@ -852,6 +852,13 @@ class Heap {
   // incremental steps.
   void StartIdleIncrementalMarking();
 
+  void StartIncrementalMarking(int gc_flags,
+                               const GCCallbackFlags gc_callback_flags);
+
+  double AdvanceIncrementalMarking(
+      intptr_t step_size_in_bytes, double deadline_in_ms,
+      IncrementalMarking::StepActions step_actions);
+
   inline void increment_scan_on_scavenge_pages() {
     scan_on_scavenge_pages_++;
     if (FLAG_gc_verbose) {
@@ -2228,10 +2235,6 @@ class Heap {
 
   GCIdleTimeHandler::HeapState ComputeHeapState();
 
-  double AdvanceIncrementalMarking(
-      intptr_t step_size_in_bytes, double deadline_in_ms,
-      IncrementalMarking::ForceCompletionAction completion);
-
   bool PerformIdleTimeAction(GCIdleTimeAction action,
                              GCIdleTimeHandler::HeapState heap_state,
                              double deadline_in_ms);